Friday, 1 March 2013

EXAMPLE PROGRAMS


EXAMPLE-1
/*
  Demonstrate a block of code.
 
  Call this file "Test.java"
*/
class Test {
  public static void main(String args[]) {
    int x, y;
 
    y = 20;

    // the target of this loop is a block
    for(x = 0; x<10; x++) {
      System.out.println("This is x: " + x);
      System.out.println("This is y: " + y);
      y = y - 2;
    }
  }
}

OUTPUT:
C:\SATYA>javac test.java
C:\satya>java test
This is x=0
This is y=20
This is x=1
This is y=18
This is x=2
This is y=16
This is x=3
This is y=14
This is x=4
This is y=12
This is x=5
This is y=10
This is x=6
This is y=8
This is x=7
This is y=6
This is x=8
This is y=4
This is x=9
This is y=2

C:\satya>

EXAMPLE-2

/*
   This is a simple Java program.
   Call this file "demo1.java".
*/
class Demo1 {
  // Your program begins with a call to main().
  public static void main(String args[]) {
    System.out.println("This is a simple Java program.");
  }
}
Output:
C:\satya>javac Demo1.java
C:\satya>java Demo1
This is a simple java program
C:\satya>

EXAMPLE-3
/*
   Here is another short example.
   Call this file "demo2.java".
*/class Demo2 {
public static void main(String args[]) {
    int num; // this declares a variable called num

    num = 10; // this assigns num the value 10
 
    System.out.println("This is num: " + num);

    num = num * 2;

    System.out.print("The value of num * 2 is ");
    System.out.println(num);
  }
}
Output:
C:\satya>javac Demo2.java
C:\satya>java Demo2
This is num:10
The value of num * 2 is 20
C:\satya>



EXAMPLE-4
/*
  Demonstrate the for loop.
 
  Call this file "Demo3.java".
*/
class Demo3 {
  public static void main(String args[]) {
    int x;
 
    for(x = 0; x<10; x = x+1)
      System.out.println("This is x: " + x);
  }
}
Output:
C:\satya>javac Demo3.java
C:\satya>java Demo3
This is x=0
This is x=1
This is x=2
This is x=3
This is x=4
This is x=5
This is x=6
This is x=7
This is x=8
This is x=9
C:\satya>



EXAMPLE-5
/*
  Demonstrate the if.
 
  Call this file "Sample.java".
*/
class Sample {
  public static void main(String args[]) {
    int x, y;

    x = 10;
    y = 20;

    if(x < y) System.out.println("x is less than y");
   
    x = x * 2;
    if(x == y) System.out.println("x now equal to y");

    x = x * 2;
    if(x > y) System.out.println("x now greater than y");

    // this won't display anything
    if(x == y) System.out.println("you won't see this");
  }
}
Output:
C:\satya>javac Sample.java
C:\satya>java Sample
X is less than y
X now equal to y
X now greater than y
C:\satya>




EXAMPLE-7
// Demonstrate a one-dimensional array.
class Array {
  public static void main(String args[]) {
    int month_days[];
    month_days = new int[12];
    month_days[0] = 31;
    month_days[1] = 28;
    month_days[2] = 31;
    month_days[3] = 30;
    month_days[4] = 31;
    month_days[5] = 30;
    month_days[6] = 31;
    month_days[7] = 31;
    month_days[8] = 30;
    month_days[9] = 31;
    month_days[10] = 30;
    month_days[11] = 31;
    System.out.println("April has " + month_days[3] + " days.");
  }
}
OUTPUT:
C:\SATYA>javac Array.java
C:\satya>java Array
April has 30 days
C:\satya>


EXAMPLE-8
// An improvied version of the previous program.
class Test1 {
  public static void main(String args[]) {
    int month_days[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
    System.out.println("April has " + month_days[3] + " days.");
  }
}
OUTPUT:
C:\SATYA>javac Test1.java
C:\satya>java Test1
April has 30 days
C:\satya>


EXAMPLE-9
// Average an array of values.
class Average {
  public static void main(String args[]) {
    double nums[] = {10.1, 11.2, 12.3, 13.4, 14.5};
    double result = 0;
    int i;
   
    for(i=0; i<5; i++)
      result = result + nums[i];

    System.out.println("Average is " + result / 5);
  }
}
OUTPUT:
C:\SATYA>javac Average.java
C:\satya>java Average
Average is 12.299999999999999
C:\satya>


EXAMPLE-10
// Demonstrate boolean values.
class Simple {
  public static void main(String args[]) {
    boolean b;

    b = false;
    System.out.println("b is " + b);
    b = true;
    System.out.pr























































intln("b is " + b);

    // a boolean value can control the if statement
    if(b) System.out.println("This is executed.");

    b = false;
    if(b) System.out.println("This is not executed.");

    // outcome of a relational operator is a boolean value
    System.out.println("10 > 9 is " + (10 > 9));
  }
}
OUTPUT:
C:\SATYA>javac Simple.java
C:\satya>java Simple
b is false
b is false
This is expected
10>9 is true
C:\satya>


EXAMPLE-11
// Demonstrate char data type.
class simple2 {
  public static void main(String args[]) {
    char ch1, ch2;

    ch1 = 88;  // code for X
    ch2 = 'Y';
   
    System.out.print("ch1 and ch2: ");
    System.out.println(ch1 + " " + ch2);
  }
}
OUTPUT:
C:\SATYA>javac simple2.java
C:\satya>java simple2
Ch1 and ch2:x y
C:\satya>

EXAMPLE-12
// char variables behave like integers.
Class charDemo {
  public static void main(String args[]) {
    char ch1;

    ch1 = 'X';
    System.out.println("ch1 contains " + ch1);

    ch1++; // increment ch1
    System.out.println("ch1 is now " + ch1);
  }
}
OUTPUT:
C:\SATYA>javac charDemo.java
C:\satya>java charDemo
Ch1 contains x
Ch1 is now y
C:\satya>


EXAMPLE-13
// Demonstrate casts.
class Conver {
  public static void main(String args[]) {
    byte b;
    int i = 257;
    double d = 323.142;
   
    System.out.println("\nConversion of int to byte.");
    b = (byte) i;
    System.out.println("i and b " + i + " " + b);

    System.out.println("\nConversion of double to int.");
    i = (int) d;
    System.out.println("d and i " + d + " " + i);

    System.out.println("\nConversion of double to byte.");
    b = (byte) d;
    System.out.println("d and b " + d + " " + b);
  }
}
OUTPUT:
C:\SATYA>javac Conver.java
C:\satya>java Conver
Conversion of int to byte
i and b 257 1
Conversion of double to int
d and i 323.142 323
Conversion of double to byte
d and b 323.142 67
c:\satya>

EXAMPLE-14
// Demonstrate dynamic initialization.
class Dynamic {
    public static void main(String args[]) {
      double a = 3.0, b = 4.0;
     
      // c is dynamically initialized
      double c = Math.sqrt(a * a + b * b);

      System.out.println("Hypotenuse is " + c);
    }
}
OUTPUT:
C:\SATYA>javac Dynamic.java
C:\satya>java Dynamic
Hypotenuse is 5.0
C:\satya>



EXAMPLE-15
// Demonstrate lifetime of a variable.
class LifeTime {
  public static void main(String args[]) {
    int x;

    for(x = 0; x < 3; x++) {
      int y = -1; // y is initialized each time block is entered
      System.out.println("y iz: " + y); // this always prints -1
      y = 100;
      System.out.println("y is now: " + y);
    }
  }
}
OUTPUT:
C:\SATYA>javac LifeTime.java
C:\satya>java LifeTime
Y is:-1
Y is now:100
Y is:-1
Y is now:100
Y is:-1
Y is now:100
C:\satya>


EXAMPLE-16
// Compute distance light travels using long variables.
class Light Demo
{
  public static void main(String args[]) {
    int lightspeed;
    long days;
    long seconds;
    long distance;

    // approximate speed of light in miles per second
    lightspeed = 186000;

    days = 1000; // specify number of days here

    seconds = days * 24 * 60 * 60; // convert to seconds

    distance = lightspeed * seconds; // compute distance

    System.out.print("In " + days);
    System.out.print(" days light will travel about ");
    System.out.println(distance + " miles.");
  }
}
OUTPUT:
C:\SATYA>javac LightDemo.java
C:\satya>java LightDemo
In 1000 days light will travel about 16070400000000 miles
C:\satya>

EXAMPLE-17
// Initialize a two-dimensional array.
class Matrix {
  public static void main(String args[]) {
    double m[][] = {
      { 0*0, 1*0, 2*0, 3*0 },
      { 0*1, 1*1, 2*1, 3*1 },
      { 0*2, 1*2, 2*2, 3*2 },
      { 0*3, 1*3, 2*3, 3*3 }
    };
    int i, j;

    for(i=0; i<4; i++) {
      for(j=0; j<4; j++)
        System.out.print(m[i][j] + " ");
      System.out.println();
    }
  }

}
OUTPUT:
C:\SATYA>javac Matrix.java
C:\satya>java matrix
0.0  0.0 0.0 0.0
0.0 1.0 2.0 3.0
0.0 2.0 4.0 6.0
0.0 3.0 6.0 9.0
C:\satya>

EXAMPLE-18
class Promote {
  public static void main(String args[]) {
    byte b = 42;
    char c = 'a';
    short s = 1024;
    int i = 50000;
    float f = 5.67f;
    double d = .1234;
    double result = (f * b) + (i / c) - (d * s);
    System.out.println((f * b) + " + " + (i / c) + " - " + (d * s));
    System.out.println("result = " + result);
  }
}
OUTPUT:
C:\SATYA>javac Promote.java
C:\satya>java Promote
238.14+515-126.3616
Result=626.7784146484375
C:\satya>


EXAMPLE-19

// Demonstrate block scope.
class Scope {
  public static void main(String args[]) {
    int x; // known to all code within main

    x = 10;
    if(x == 10) { // start new scope
      int y = 20; // known only to this block

      // x and y both known here.
      System.out.println("x and y: " + x + " " + y);
      x = y * 2;
    }
    // y = 100; // Error! y not known here

    // x is still known here.
    System.out.println("x is " + x);
  }
}
OUTPUT:
C:\SATYA>javac Scope.java
C:\satya>java Scope
X and y:10 20
X is 40


EXAMPLE-20

// This program will not compile
class ScopeErr {
   public static void main(String args[]) {
     int bar = 1;
class threeDMatrix {
     {              // creates a new scope
       int bar = 2; // Compile time error -- bar already defined!
     }
   }
}
OUTPUT:
C:\SATYA>javac ScopeErr.java
C:\satya>java ScopeErr
Compile run time—bar already defined
C:\satya>


EXAMPLE-21

// Demonstrate a three-dimensional array.
Class threeDarray
  public static void main(String args[]) {
    int threeD[][][] = new int[3][4][5];
    int i, j, k;
   
    for(i=0; i<3; i++)
      for(j=0; j<4; j++)
        for(k=0; k<5; k++)
        threeD[i][j][k] = i * j * k;

    for(i=0; i<3; i++) {
      for(j=0; j<4; j++) {
        for(k=0; k<5; k++)
          System.out.print(threeD[i][j][k] + " ");
        System.out.println();
      }
      System.out.println();
    }
  }
}
OUTPUT:
C:\SATYA>javac threeDarrray.java
C:\satya>java threeDarray
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0

0 0 0 0 0
0 1 2 3 4
0 2 4 6 8
0 3 6 9 12

0 0 0 0 0
0 2 4 6 8
 0 4 8 12 16
0 6 12 18 24
C:\satya>

EXAMPLE-22

// Manually allocate differing size second dimensions.
class TwoDAgain {
  public static void main(String args[]) {
    int twoD[][] = new int[4][];
    twoD[0] = new int[1];
    twoD[1] = new int[2];
    twoD[2] = new int[3];
    twoD[3] = new int[4];

    int i, j, k = 0;

    for(i=0; i<4; i++)
      for(j=0; j<i+1; j++) {
        twoD[i][j] = k;
        k++;
      }

    for(i=0; i<4; i++) {
      for(j=0; j<i+1; j++)
        System.out.print(twoD[i][j] + " ");
      System.out.println();
    }
  }
}
OUTPUT:
C:\SATYA>javac TwoDAgain.java
C:\satya>java TwoDAgain
0
1 2
3 4 5
6 7 8 9
C:\satya>



EXAMPLE-23

// Demonstrate a two-dimensional array.
class TwoDArray {
  public static void main(String args[]) {
    int twoD[][]= new int[4][5];
    int i, j, k = 0;

    for(i=0; i<4; i++)
      for(j=0; j<5; j++) {
        twoD[i][j] = k;
        k++;
      }

    for(i=0; i<4; i++) {
      for(j=0; j<5; j++)
        System.out.print(twoD[i][j] + " ");
      System.out.println();
    }
  }
}
OUTPUT:
C:\SATYA>javac TwoDarrray.java
C:\satya>java TwoDarray
0 1 2 3 4
5 6 7 8 9
10 11 12 13 14
15 16 17 18 19
C:\satya>



EXAMPLE-24

// Demonstrate the basic arithmetic operators.
class Basic {
  public static void main(String args[]) {
    // arithmetic using integers
    System.out.println("Integer Arithmetic");
    int a = 1 + 1;
    int b = a * 3;
    int c = b / 4;
    int d = c - a;
    int e = -d;
    System.out.println("a = " + a);
    System.out.println("b = " + b);
    System.out.println("c = " + c);
    System.out.println("d = " + d);
    System.out.println("e = " + e);

    // arithmetic using doubles
    System.out.println("\nFloating Point Arithmetic");
    double da = 1 + 1;
    double db = da * 3;
    double dc = db / 4;
    double dd = dc - a;
    double de = -dd;
    System.out.println("da = " + da);
    System.out.println("db = " + db);
    System.out.println("dc = " + dc);
    System.out.println("dd = " + dd);
    System.out.println("de = " + de);
  }
}
OUTPUT:
C:\SATYA>javac Basic.java
C:\satya>java Basic
Integer Arthimetic
a=2
b=6
c=1
d=-1
e=1
Floating point Arithmetic
da=2.0
db=6.0
dc=1.5
dd=-0.5
de=0.5
c:\satya>



EXAMPLE-25
// Demonstrate the bitwise logical operators.
class BitLogic {
  public static void main(String args[]) {
    String binary[] = {
      "0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111",
      "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"
    };
    int a = 3; // 0 + 2 + 1 or 0011 in binary
    int b = 6; // 4 + 2 + 0 or 0110 in binary
    int c = a | b;
    int d = a & b;
    int e = a ^ b;
    int f = (~a & b) | (a & ~b);
    int g = ~a & 0x0f;

    System.out.println("        a = " + binary[a]);
    System.out.println("        b = " + binary[b]);
    System.out.println("      a|b = " + binary[c]);
    System.out.println("      a&b = " + binary[d]);
    System.out.println("      a^b = " + binary[e]);
    System.out.println("~a&b|a&~b = " + binary[f]);
    System.out.println("       ~a = " + binary[g]);
  }
}
OUTPUT:
C:\SATYA>javac BitLogic.java
C:\satya>java BitLogic
a=0011
b=0110
a|b=0111
a&b=0010
a^b=0101
~a&b|a&~b=0101
~a=1100
C:\satya>


EXAMPLE-26

// Demonstrate the boolean logical operators.
Class vera
{
  public static void main(String args[]) {
    boolean a = true;
    boolean b = false;
    boolean c = a | b;
    boolean d = a & b;
    boolean e = a ^ b;
    boolean f = (!a & b) | (a & !b);
    boolean g = !a;

    System.out.println("        a = " + a);
    System.out.println("        b = " + b);
    System.out.println("      a|b = " + c);
    System.out.println("      a&b = " + d);
    System.out.println("      a^b = " + e);
    System.out.println("!a&b|a&!b = " + f);
    System.out.println("       !a = " + g);
  }
}
OUTPUT:
C:\SATYA>javac vera.java
C:\satya>java vera
a=true
b=false
a|b=true
a&b=false
a^b=true
!a&b|a&!b=true
!a=false
C:\satya>

EXAMPLE-27

// Left shifting a byte value.
class Shift {
  public static void main(String args[]) {
    byte a = 64, b;
    int i;
    i = a << 2;
    b = (byte) (a << 2);
    System.out.println("Original value of a: " + a);
    System.out.println("i and b: " + i + " " + b);
  }
}
OUTPUT:
C:\SATYA>javac Shift.java
C:\satya>java Shift
Original value of a:64
i and b:256 0
c:\satya>


EXAMPLE-28

// Unsigned shifting a byte value.
class ByteUShift {
  static public void main(String args[]) {
    char hex[] = {
      '0', '1', '2', '3', '4', '5', '6', '7',
      '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
    };
    byte b = (byte) 0xf1;
    byte c = (byte) (b >> 4);
    byte d = (byte) (b >>> 4);
    byte e = (byte) ((b & 0xff) >> 4);

    System.out.println("              b = 0x"
      + hex[(b >> 4) & 0x0f] + hex[b & 0x0f]);
    System.out.println("         b >> 4 = 0x"
      + hex[(c >> 4) & 0x0f] + hex[c & 0x0f]);
    System.out.println("        b >>> 4 = 0x"
      + hex[(d >> 4) & 0x0f] + hex[d & 0x0f]);
    System.out.println("(b & 0xff) >> 4 = 0x"
      + hex[(e >> 4) & 0x0f] + hex[e & 0x0f]);
  }
}
OUTPUT:
C:\SATYA>javac ByteUShift.java
C:\satya>java ByteUshift
                                b=0*f1
                         b>>4=0*ff
                     b>>>4=0*ff
                 <b & 0*ff> >>4=0*0f
C:\satya>

EXAMPLE-29

// Masking sign extension.
class HexByte {
  static public void main(String args[]) {
    char hex[] = {
      '0', '1', '2', '3', '4', '5', '6', '7',
      '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
    };
    byte b = (byte) 0xf1;

    System.out.println("b = 0x" + hex[(b >> 4) & 0x0f] + hex[b & 0x0f]);
  }}
OUTPUT:
C:\SATYA>javac HexByte.java
C:\satya>java HexByte
b=0*f1
c:\satya>


EXAMPLE-30

// Demonstrate ++ and --.
class IncDec {
  public static void main(String args[]) {
    int a = 1;
    int b = 2;
    int c;
    int d;

    c = ++b;
    d = a++;
    c++;
    System.out.println("a = " + a);
    System.out.println("b = " + b);
    System.out.println("c = " + c);
    System.out.println("d = " + d);
  }
}
OUTPUT:
C:\SATYA>javac IncDec.java
C:\satya>java IncDec
a=2
b=3
c=4
d=1
c:\satya>


EXAMPLE-31

// Demonstrate the % operator.
class Modulus {
  public static void main(String args[]) {
    int x = 42;
    double y = 42.3;

    System.out.println("x mod 10 = " + x % 10);
    System.out.println("y mod 10 = " + y % 10);
  }
}
OUTPUT
C:\Sai>javac Modulus.java
C:\Sai>java Modulus
X mod 10 = 2
Y mod 10 = 2.99999999999997
C:\Sai>

           
EXAMPLE-32

// Left shifting as a quick way to multiply by 2.
class Multi{
  public static void main(String args[]) {
    int i;
    int num = 0xFFFFFFE;

    for(i=0; i<4; i++) {
      num = num << 1;
      System.out.println(num);
    } } }

OUTPUT
C:\Sai>javac Multi.java
C:\Sai>java Multi
5367870908
1073741816
2147483632
-32
C:\Sai>

EXAMPLE-33

class Equals {
  public static void main(String args[]) {
    int a = 1;
    int b = 2;
    int c = 3;
    a |= 4;
    b >>= 1;
    c <<= 1;
    a ^= c;
    System.out.println("a = " + a);
    System.out.println("b = " + b);
    System.out.println("c = " + c);
  }}

OUTPUT
C:\Sai>javac Equals.java
C:\Sai>java Equals
   a = 3
   b = 1
   c = 6
C:\Sai>
EXAMPLE-34
// Demonstrate several assignment operators.
class op{
  public static void main(String args[]) {
    int a = 1;
    int b = 2;
    int c = 3;

    a += 5;
    b *= 4;
    c += a * b;
    c %= 6;
    System.out.println("a = " + a);
    System.out.println("b = " + b);
    System.out.println("c = " + c);
  }
}
OUTPUT
C:\Sai>javac op.java
C:\Sai>java op
   a = 6
   b = 8
   c = 3
C:\Sai>


EXAMPLE-35
// Demonstrate ?.
class Ternary {
  public static void main(String args[]) {
    int i, k;

    i = 10;
    k = i < 0 ? -i : i; // get absolute value of i
    System.out.print("Absolute value of ");
    System.out.println(i + " is " + k);

    i = -10;
    k = i < 0 ? -i : i; // get absolute value of i
    System.out.print("Absolute value of ");
    System.out.println(i + " is " + k);
  }
}
OUTPUT
C:\Sai>javac Ternary.java
C:\Sai>java Ternary
Absolute value of 10 is 10
Absolute value of -10 is -10
C:\Sai>



EXAMPLE-36

// Using break as a civilized form of goto.
Class br{
  public static void main(String args[]) {
    boolean t = true;

    first: {
      second: {
        third: {
          System.out.println("Before the break.");
          if(t) break second; // break out of second block
          System.out.println("This won't execute");
        }
        System.out.println("This won't execute");
      }
      System.out.println("This is after second block.");
    }
  }
}
OUTPUT
C:\Sai>javac br.java
C:\Sai>java br
Before the break
This is after second block.
C:\Sai
EXAMPLE-37

// This program contains an error.
class BreakErr {
  public static void main(String args[]) {

    one: for(int i=0; i<3; i++) {
      System.out.print("Pass " + i + ": ");
    }

    for(int j=0; j<100; j++) {
      if(j == 10) //break one; // WRONG
      System.out.print(j + " ");
    }
  }
}
OUTPUT
C:\Sai>javac BreakErr.java
C:\Sai>java BreakErr
Pass  0: Pass 1: Pass 2: 10
C:\Sai>

EXAMPLE-38

// Using break to exit a loop.
class BreakLoop {
  public static void main(String args[]) {
    for(int i=0; i<100; i++) {
      if(i == 10) break; // terminate loop if i is 10
      System.out.println("i: " + i);
    }
    System.out.println("Loop complete.");
  }
}

OUTPUT
C:\Sai>javac BreakLoop.java
C:\Sai>java BreakLoop
i: 0
i: 1
i: 2
i: 3
i: 4
i: 5
i: 6
i: 7
i: 8
i: 9
Loop complete.
C:\Sai>








EXAMPLE-39

// Using break to exit a while loop.
class BreakLoop2 {
  public static void main(String args[]) {
    int i = 0;
   
    while(i < 100) {
      if(i == 10) break; // terminate loop if i is 10
      System.out.println("i: " + i);
      i++;
    }
    System.out.println("Loop complete.");
  }
}
OUTPUT
C:\Sai>javac BreakLoop2.java
C:\Sai>java BreakLoop2
i: 0
i: 1
i: 2
i: 3
i: 4
i: 5
i: 6
i: 7
i: 8
i: 9
Loop complete.
C:\Sai>









EXAMPLE-40

// Using break to exit from nested loops
class Loop4 {
  public static void main(String args[]) {
    outer: for(int i=0; i<3; i++) {
      System.out.print("Pass " + i + ": ");
      for(int j=0; j<100; j++) {
        if(j == 10) break outer; // exit both loops
        System.out.print(j + " ");
      }
      System.out.println("This will not print");
    }
    System.out.println("Loops complete.");
  }
}
OUTPUT
C:\SATYA>javac Loop4.java
C:\SATYA>java Loop4
Pass 0: 0 1 2 3 4 5 6 7 8 9  Loops complete

C:\SATYA>

EXAMPLE-41

// Using the comma.
class pro{
  public static void main(String args[]) {
    int a, b;

    for(a=1, b=4; a<b; a++, b--) {
      System.out.println("a = " + a);
      System.out.println("b = " + b);
    }
  }
}
OUTPUT


C:\SATYA>javac pro.java
C:\SATYA>java pro
a = 1
b = 4
a = 2
b = 3
C:\SATYA>






EXAMPLE-43

// Demonstrate continue.
class Continue {
  public static void main(String args[]) {
    for(int i=0; i<10; i++) {
      System.out.print(i + " ");
      if (i%2 == 0) continue;
      System.out.println("");
    }
  }
}
OUTPUT
C:\SATYA>javac Continue.java
C:\SATYA>java Continue
0 1
2 3
4 5
6 7
8 9
C:\SATYA>


EXAMPLE-44

// Using continue with a label.
class ContinueLabel {
  public static void main(String args[]) {
outer: for (int i=0; i<10; i++) {
         for(int j=0; j<10; j++) {
           if(j > i) {
             System.out.println();
             continue outer;
           }
           System.out.print(" " + (i * j));
         }
       }
       System.out.println();
  }
}
OUTPUT
C:\SATYA>javac ContinueLabel.java
C:\SATYA>java ContinueLabel
0
0   1
0   2    4
0   3    6    9
0   4    8   12  16
0   5   10  15  20  25
0   6   12  18  24  30   36
0   7   14  21  28  35   42  49
0   8   16  24  32  40   48   56    64
0   9   18  27  36  45   54   63   72  81
C:\SATYA>


EXAMPLE-45

// Demonstrate the do-while loop.
class DoWhile {
  public static void main(String args[]) {
    int n = 10;

    do {
      System.out.println("tick " + n);
      n--;
    } while(n > 0);
  }
}

OUTPUT
C:\SATYA>javac DoWhile.java
C:\SATYA>java  DoWhile
Tick 10
Tick  9
Tick  8
Tick  7
Tick  6
Tick  5
Tick  4
Tick  3
Tick  2
Tick  1

C:\SATYA>







EXAMPLE-46

// Test for primes.
class Prime {
  public static void main(String args[]) {
    int num;
    boolean isPrime = true;

    num = 14;
    for(int i=2; i < num/2; i++) {
      if((num % i) == 0) {
        isPrime = false;
        break;
      }
    }
    if(isPrime) System.out.println("Prime");
    else System.out.println("Not Prime");
  }
}
OUTPUT
C:\SATYA>javac Prime.java
C:\SATYA>java  Prime
Not  Prime

C:\SATYA>


EXAMPLE-48

// Declare a loop control variable inside the for.
class ForTick1 {
  public static void main(String args[]) {

    // here, n is declared inside of the for loop
    for(int n=10; n>0; n--)
      System.out.println("tick " + n);
  }
}
OUTPUT
C:\SATYA>javac ForTick1.java
C:\SATYA>java  ForTick1
Tick 10
Tick 9
Tick 8
Tick 7
Tick 6
Tick 5
Tick 4
Tick 3
Tick 2
Tick 1
C:\SATYA>
EXAMPLE-49

// Parts of the for loop can be empty.
class ForVar {
  public static void main(String args[]) {
    int i;
    boolean done = false;

    i = 0;
    for( ; !done; ) {
      System.out.println("i is " + i);
      if(i == 10) done = true;
      i++;
    }
  }
}
OUTPUT
C:\SATYA>javac ForVar.java
C:\SATYA>java  ForVar
i  is 0
i  is 1
i  is 2
i  is 3
i  is 4
i  is 5
i  is 6
i  is 7
i  is 8
i  is 9
i  is 10
C:\SATYA>
EXAMPLE-50

// Demonstrate if-else-if statements.
class pro2{
  public static void main(String args[]) {
    int month = 4; // April
    String season;

    if(month == 12 || month == 1 || month == 2)
      season = "Winter";
    else if(month == 3 || month == 4 || month == 5)
      season = "Spring";
    else if(month == 6 || month == 7 || month == 8)
      season = "Summer";
    else if(month == 9 || month == 10 || month == 11)
      season = "Autumn";
    else
      season = "Bogus Month";

    System.out.println("April is in the " + season + ".");
  }
}
OUTPUT
C:\SATYA>javac pro2.java
C:\SATYA>java  pro2
April  is  in the Spring.
C:\SATYA>


EXAMPLE-51

// Using a do-while to process a menu selection -- a simple help system.
class Menu {
  public static void main(String args[])
    throws java.io.IOException {
    char choice;

    do {
      System.out.println("Help on:");
      System.out.println("  1. if");
      System.out.println("  2. switch");
      System.out.println("  3. while");
      System.out.println("  4. do-while");
      System.out.println("  5. for\n");
      System.out.println("Choose one:");
      choice = (char) System.in.read();
    } while( choice < '1' || choice > '5');

    System.out.println("\n");

    switch(choice) {
      case '1':
        System.out.println("The if:\n");
        System.out.println("if(condition) statement;");
        System.out.println("else statement;");
        break;
      case '2':
        System.out.println("The switch:\n");
        System.out.println("switch(expression) {");
        System.out.println("  case constant:");
        System.out.println("    statement sequence");
        System.out.println("  break;");
        System.out.println("  // ...");
        System.out.println("}");
        break;
      case '3':
        System.out.println("The while:\n");
        System.out.println("while(condition) statement;");
        break;
      case '4':
        System.out.println("The do-while:\n");
        System.out.println("do {");
        System.out.println("  statement;");
        System.out.println("} while (condition);");
        break;
      case '5':
        System.out.println("The for:\n");
        System.out.print("for(init; condition; iteration)");
        System.out.println(" statement;");
        break;
    }
  }
}
OUTPUT
C:\SATYA>javac Menu.java
C:\SATYA>java  Menu
Help on:
1. if
2. switch
3. while
4. do-while
5.  for

Choose one:  1
 
if<condition> statement;
else statement;
C:\SATYA>

EXAMPLE-52

// In a switch, break statements are optional.
Class pro1{
  public static void main(String args[]) {
    for(int i=0; i<12; i++)
      switch(i) {
        case 0:
        case 1:
        case 2:
        case 3:
        case 4:
          System.out.println("i is less than 5");
          break;
        case 5:
        case 6:
        case 7:
        case 8:
        case 9:
          System.out.println("i is less than 10");
          break;
        default:
          System.out.println("i is 10 or more.");
      }
  }
}
OUTPUT
C:\SATYA>javac pro1.java
C:\SATYA>java  pro1
i  is less than 5
i  is less than 5
i  is less than 5
i  is less than 5
i  is less than 5
i  is less than 10
i  is less than 10
i  is less than 10
i  is less than 10
i  is less than 10
i  is 10 or more
i  is 10 or more
C:\SATYA>




EXAMPLE-53

// Loops may be nested.
class Nested {
  public static void main(String args[]) {
    int i, k;

    for(i=0; i<10; i++) {
      for(k=i;k<10;k++)
        System.out.print(".");
      System.out.println();
    }
  }
}
OUTPUT
C:\SATYA>javac Nested.java
C:\SATYA>java  Nested
. . . . . . . . . . .
. . . . . . . . . .
. . . . . . . . .
. . . . . . . .
. . . . . . .
. . . . . .
. . . . .
. . . .
. . .
. .
.
C:\SATYA>


EXAMPLE-54

// The target of a loop can be empty.
class  target{
  public static void main(String args[]) {
    int i, j;

    i = 100;
    j = 200;

    // find midpoint between i and j
    while(++i < --j) ; // no body in this loop

    System.out.println("Midpoint is " + i);
  }
}
OUTPUT
C:\SATYA>javac target.java
C:\SATYA>java  target
Midpoint is 150
C:\SATYA>

EXAMPLE-55

// Demonstrate return.
class Return {
  public static void main(String args[]) {
    boolean k= true;

    System.out.println("Before the return.");

    if(k) return // return to caller

    System.out.println("This won't execute.");
  }
}
OUTPUT

Error

EXAMPLE-56

class Sample3{
  public static void main(String args[]) {
    int a, b;

    b = 4;
    for(a=1; a<b; a++) {
      System.out.println("a = " + a);
      System.out.println("b = " + b);
      b--;
    }
  }
}
OUTPUT
C:\SATYA>javac Sample3.java
C:\SATYA>java  Sample
a = 1
b = 4
a = 2
b = 3
C:\SATYA>


EXAMPLE-57

// A simple example of the switch.
Class Switch3{
  public static void main(String args[]) {
    for(int i=0; i<6; i++)
      switch(i) {
        case 0:
          System.out.println("i is zero.");
          break;
        case 1:
          System.out.println("i is one.");
          break;
        case 2:
          System.out.println("i is two.");
          break;
        case 3:
          System.out.println("i is three.");
          break;
        default:
          System.out.println("i is greater than 3.");
      }
  }
}
OUTPUT

C:\SATYA>javac Switch3.java
C:\SATYA>java  Switch3
i is zero
i is one
i is two
i is three
i is greater than 3
i is greater than 3
C:\SATYA>





EXAMPLE-58

// An improved version of the season program.
class Session{
    public static void main(String args[]) {
        int month = 4;
        String season;
        switch (month) {
          case 12:
          case 1:
          case 2:
            season = "Winter";
            break;
          case 3:
          case 4:
          case 5:
            season = "Spring";
            break;
          case 6:
          case 7:
          case 8:
            season = "Summer";
            break;
          case 9:
          case 10:
          case 11:
            season = "Autumn";
            break;
          default:
            season = "Bogus Month";
        }
        System.out.println("April is in the " + season + ".");
    }
}
OUTPUT:
C:\SATYA>javac Session.java
C:\satya>java Session
April is in the spring
C:\satya>


EXSAMPLE-59

// Demonstrate the while loop.
class Loop
  public static void main(String args[]) {
    int n = 10;

    while(n > 0) {
      System.out.println("tick " + n);
      n--;
    }
  }
}
OUTPUT:
C:\SATYA>javac Loop.java
C:\satya>java Loop
Tick 10
Tick 9
Tick 8
Tick 7
Tick 6
Tick 5
Tick 4
Tick 3
Tick 2
Tick 1
C:\satya>




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