For Loop Condition in C

For loop is use in program when we know the number of iteration. How much iteration go long.? We exactly know the number of iteration.

Syntax of for loop:

	
    for(initialization; condition; updation)
    {
    statement;
    }
    

Rules of for loop:

• Initialization Optional
• Condition Optional
• Updation Optional

Initialization Optional

Initialization in for loop brackets is optional. You can set the initialization outside of the loop.

Syntax of for loop optional initialization:

	
    initialization;
    
    for (; condition; updation)
    {
    statement
    }
    

Condition Optional

Condition is also optional in for loop brackets. You can set the condition outside of the loop

Syntax of for loop optional condition:

	
    initialization;
    condition;
    
    for (; ; updation)
    {
    statement;
    }
    

Updation Optional

Updation is also optional in for loop brackets.

But semi-column ( ; ) is necessary in for loop bracket.

Syntax of for loop optional updation:

	
    initialization;
    condition;
    
    for (; ;)
    {
    statement;
    updation;
    }
    

How for loop work?

Step 1.

for loop only one time go inside the initialization.

Step 2.

for loop check condition until it not become false.

Step 3.

Execute the body portion.

Step 4.

Next it will go for updation.

step 2, step 3 and step 4 go until condition not become false. It will keep performing the iteration until condition not become false. At last it will come out from the loop body.

See the image for more understanding

Example 1 of for loop program:

    #include<stdio.h>
    #include<conio.h>
    
    void main()
    {
    	int i;
        
        printf("Printing the number from 1 to 10.\n");
        for(i=1; i<=10; i++)
        {
        printf(" %d \n",i);
        }
        
        getch();
    }
 

Output:

 
    Printing the number from 1 to 10.
    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    

Example 2 of for loop program:

	
    #include<stdio.h>
    #include<conio.h>
	
    //program of table 2.
    void main()
    {
	    int i;
	    int fact;
	    clrscr();
	    
        for(i=1; i<=10; i++)
	    {
	    fact = i*2;
	    printf("%d\n",fact);
	    }
	    getch();
    }
    

Output:

	
    2
    4
    6
    8
    10
    12
    14
    16
    18
    20