Loop Structure

It is aslo known as repetitive structure. Loop structure is used to run the block of codes until the condition is satisfied. While in execution, the if the condition is true then it is executed if the condition is false then the loop is terminated and follows the next statement of loop. Loop structure continue to execute until the condition is satisfied and it is very useful in many areas because of this feature.

 In java programming language, there are three options to use repetitive structure.
1) 'while' statement
2)'do-while' statement
3)'for' statement

1)'while' statement

In while statement, certain code of block runs which is inside the while loop structure until the condition becomes false. After being the condition false, the loop will terminate itself. Syntax:-

while(<condition expression>)
{
     //program code
}

2)'do-while' statement

It is also a type of statement. In this type of structure, while expression is used at the last of the loop structure. In While loop, at first the condition is checked and if the condition is true then it runs the block of code. in do-while loop, at first the statement is run and then check the condition. Note that at the end of while expression ' ; ' must be used.Syntax:-

do{
   //program code
}while(condidion);

3)'for' statement

This structure helps us to run the certain block of code for a fix number of time. We can say that, it is just like saying 'repeat the condition for 50 times or 100, as required per your need'. Syntax:-

for(int i=0;i<10;i++){
    System.out.prinltn("number"+i);
}

The break statement

We used break statement is the switch case.The break statement is used to terminate the loop in execution of the code. Syntax:-

public class BreakDemo
{
         public static void(String args[])
        {
             int a=1;
             while(a<10)
              {
                 System.out.println("number"+a);
                 if(a==10)
                  break;
                  a++;
               }
        }
}

The continue statement


The continue statement skips the current step of iteration of a for, while, or do-while  loop. It however does not break out from the loop block, but instead returning to the  point where the termination condition expression is evaluated. Figure 3.16  demonstrates the use of continue statement. The programme prints even number  because whenever a % 2 != 0, i.e. odd number, the continue statement is executed and  the code skip the rest of the code after the continue statement. Flow is returned to  the beginning of the for loop. Syntax:-

public class ContinueDemo
{
     public static void main(String arg[]){
     int a;
     for(a=0;a<11;a++)
     {
        if(a %2!=0)
        continue;
        System.out.println("number"+a);
      }

}