For Loop

For loop

Syntax

    for(initialization; expr; inc/dec expr){
       //body 
    }

The 3 parts of the for loop are initialization, expression and increment/decrement, they should be separated by semicolon ;

Flowchart

flowchart TD A[Initialize the loop] --> B{check expression} B --> |True| C[Execute for block] B --> |False| D(Loop terminate) C --> E[increment / decrement] E --> B

for loop is initialized first and then the boolean expression is checked. If the expression evaluates to true, then the for block is executed, otherwise the loop terminates. If the for block is executed, then the increment or decrement updated to continue the loop

Examples

public class Demo28{
    public static void main(String[] args) {
        for (int i=1;i<=5;i++){
            System.out.println(i);
        }
    }
}

Output:
1
2
3
4
5

public class Demo29{
    public static void main(String[] args) {
        for(int i=10; i > 5; i--){
            System.out.println(i);
        }
    }
}

Output:
10
9
8
7
6

public class Demo30{
    public static void main(String[] args) {
        int i =1,j;
        for (j = 1; i <=5; ) {
            System.out.println("i= " + i);
            System.out.println("j= " + j);
            i++;
        }
    }
}

Output:
i= 1
j= 1
i= 2
j= 1
i= 3
j= 1
i= 4
j= 1
i= 5
j= 1