Java for loop is used, when you know exactly how many times you want to loop through a block of code.
Syntax of For Loop :
for ( initialization ; condition ; increament/decrement ) {
//code to be executed repeatedly
}
initialization : This initialisation statement is executed once at the beginning of the loop which is used to declare and initialize a loop control variable .
Example: int i= 0 ;
condition : This condition statement which is of type boolean is evaluated before each iteration of the loop . If the condition evaluates to be true, the block of code within the for loop is executed . If it is false , the loop terminates.
Example : i<5 ;
increment/decrement : This increment or decrement statement is executed after each iteration of the loop . It is mostly used to update the loop control variable.
Example : i++ or i—;
Example of for Loop :
Example1: Print numbers from 1 to 5 using for loop.
for ( int i= 1; i<=5; i++ ) {
System.out.println (i);
}
Example 2 : Print the even numbers between 0 and 15
for ( int i=0 ; i <=15 ; i=i+2 ) {
System.out.println(i);
}
Example 3 : Print the sum of numbers from 1 to 7 using for loop
int sum=0;
for ( int i=1 ; i <= 7 ; i++ ) {
sum=sum+i;
}
System.out.println(” Sum is : “+sum);
Example 4 : Prints a countdown from 7 to 1 :
for ( int i=7 ; i>0 ; i– ) {
System.out.println(i);
}
For Loop with False Condition : If the condition inside a for loop is false from the start, the code inside the for loop will be skipped entirely .
Example :
for ( int i=7 ;i<3;i++ ){
System.out.println(“This will never print as condition inside this for loop is false “);
}