Java Beginner Tutorial # 6 : Loops

Loops

are used to iterate sets of instructions through code blocks for a set number of times.

Three types of loops:

  • while loop
  • for loop
  • do while loop

While Loop

will continue to execute instructions as long as the conditions are True

class Main {

   public static void main(String args[]) {
      int x = 5, y = 10;

      while( x < y ) {
         System.out.print("value of x : " + x );
         x++;
         System.out.print("\n");
      }
   }
}
Output
value of x : 5
value of x : 6
value of x : 7
value of x : 8
value of x : 9

For Loop

are similar to while loops, but are much more convenient to write. 

class Main {

   public static void main(String args[]) {

        for (int x = 5,y = 10; x <= y; x++) 
            System.out.println("Value of x:" + x); 
}
}
Output : 
Value of x:5
Value of x:6
Value of x:7
Value of x:8
Value of x:9
Value of x:10

do while Loop

gives a set of instructions to carry out while certain conditions are being met

class Main {
 public static void main(String args[]) 
    { 
        int x = 5; 
        do
        { 
            //Instruction  
            System.out.println("Value of x:" + x); 
            x++; 
        } 
        // Condition being met
        while (x < 10); 
    } 
}
Output : 
Value of x:5
Value of x:6
Value of x:7
Value of x:8
Value of x:9
Value of x:10
Click here for Part Seven : How to create Methods