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C language for statement with example

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C language for statement with example

In this tutorial, we will discuss the C language for statement with example

generally in programming languages, looping statements used to perform of a condition of the block of code.

C program has 3 looping statement

for loop
while loop
do-while loop

here we can clearly understand for loop in C language

Syntax

for ( initializationstatement; condition; increment/dicrement ) {
statement(s);
}

Flow diagram for loop in C

Flow diagram

How for loops works

first the initialization statements are executed only once

Then the test expression is evaluated when the test expression becomes false. The control comes out from the loop and for loop is terminated.
However, when the test expression evaluated to true, statements inside the body of for loop are executed.
finally, the updating statement(increment/decrement) is updated

then again the test expression is evaluated
This process happening on until the test expression becomes false.

Example

Syntax

For loop starts from initialization statements.

The test expression is evaluated. if the test expression is false (boolean check), the flow of control skips from the loop. for loop is terminated, but if the test expression is true codes inside in the body of for loop is executed and then update statement is updated.

this process repeats until the test expression is false. when test expression false, The for loop is terminated

program 1

#include <stdio.h>
#include <stdlib.h>

int main()
{
int a;

/* for loop execution*/
for(a=10; a<20; a=a+1){

printf(“value of a is %dn”,a);
}

return 0;
}

program 2

//program to calculate the sum of first n natural numbers

//Enter a positive integer and calculate sum

#include <stdio.h>

#include <stdlib.h>

int main()

{

int n,count,sum=0;

printf(“Enter a positive integer:”);

scanf(“%d”, &n);

//for loop terminates when n is less then count

for(count=1; count<=n; ++count)

{

sum+=count;

}

printf(“sum = %d”, sum);

return 0;

}

Find factorial of the number

#include <stdio.h>
#include <stdlib.h>

int main()
{
int n,i;
long factorial=1;

printf(“Enter an integer number..”);
scanf(“%d”,&n);

// show error if user enter a negetive integer
if(n<=0){
printf(“Error you must enter positive numbern”);
}
else{
for(i=1; i<=n; ++i) // single for loop
{
factorial*=i;
}
printf(“factorial of %d=%11u”,n,factorial);
}
return 0;

}

Nested for loop

for (initialization; condition; increment/decrement)

{

statement(s);

for (initialization; condition; increment/decrement)

{

statement(s);

… … …

}

… … …

}

program 1

#include <stdio.h>
#include <stdlib.h>

int main()
{
int row,coloum,n;
printf(“Enter the rectabgle sizen”);
scanf(“%d”,&n);

for(row=1; row<=n; row++){
for(coloum=1; coloum<=n; coloum++){
printf(“*”);
}
printf(“n”);
}

return 0;
}