Explain break statement in a loop ?

A break statement exits a loop before an entry condition fails. For instance, in this variation on the CountWheat program an error message is printed, and you break out of the for loop if j becomes negative.

class CountWheat  {

   public static void main (String args[]) {

      int total = 0;

     for (int square=1, grains = 1; square <= 64; square++) {

      grains *= 2;

      if (grains <= 0) {

        System.out.println("Error: Overflow");

        break;

      }

      total += grains;

      System.out.print(total + "\t  ");

      if (square % 4 == 0) System.out.println();

    } 

    System.out.println("All done!");

   }

 }

Here's the output:

% javac CountWheat.java

% java CountWheat

2            6           14              30

62           126         254             510

1022         2046        4094            8190

16382        32766       65534           131070

262142       524286      1048574         2097150

4194302      8388606     16777214        33554430

67108862     134217726   268435454       536870910

1073741822   2147483646      Error: Overflow

All done!

The most general use of break is in switch statements.