for statement in c language | Nesting of for in c language

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for statement in c language

for statement is a looping statement used to repeat a set of statements for a specified number of times. Syntax of for statement is:

for(Initialize;Condition;Update)
{
Statements;
}
for is a predefined keyword of C Language .

Initialize:  In this part, we assign some value to the control variable which controls number of times the loop should execute.

Example

i=1;

Condition: It is a relational or logical expression to verify whether the for statement should continue or not.

Example

i<=5;

Update: Increasing or decreasing the value of control variable comes under this part.

Example

i++

Statements are set of instructions which will repeatedly execute as long as condition evaluates to true.

Example:

for(k=1;k<=4;k++)

k=1 is the initialization.

k<=4 is the condition.

k++ is the updation.



Program 
#include<stdio.h>
int main()
{
int k;
for(k=1;k<=4;k++)
printf(“\n%d”,k);
return(0);
}
Output
1
2
3
4

Description of above program

In the program, control variable k has been strored value 1. Value of k is then compared with 4. It is less than 4, so statement printf(“\n%d”,k) gets executed showing value of k i.e. 1.

Then control goes to updation statement k++which increases the value of k by 1. k becomes 2.

Again k<=5 is tested. which is true so printf(“\n%d”,k); gets executed.

Again updation k++ is performed followed by condition k<=4. This process goes on as long as condition is true.



Nesting of for statement

In this case one for statement is enclosed within another for statement.

Program
#include<stdio.h>
int main()
{
in out,in;
for(out=1;  out<=3;  out++)
{
      for(in=1;  in<=3;  in++)
      printf(“\n%d,%d”,out,in);
}
return(0);
}
Output
1,1
1,2
1,3
2,1
2,2
2,3
3,1
3,2
3,3

Description of above program

In the above program, for one value of outer loop, inner loop will execute completely

for out=1, in  will execute complete i.e. 1,2,3.

for out=2, in will again execute complete i.e. 1,2,3.

Similarly for out=3, in will work complete i.e. 1,2,3.

This process is repeated for next values of out i.e. 2 and 3.



Lesson tags: for statement of c, looping statements in c, nesting of for statement in c
Back to: C Programming Language