In this lesson, we will learn about ‘for-loop’ in C programming which is used to iterate itself. For loop provides a mechanism to repeat the task until a particular condition in the expression part is true.

syntax of for loop in C

for (initialization; condition; increment / decrement) {
  statement block;
}
statement y;

For loop is also known as a definite or determinate loop. Inside the parenthesis of the for loop, we use three statements:

for loop in C explained

• In the first step, the initialization of the variable takes place.
• In the next step, the compiler checks the condition part. If it is true, then increment or decrement of the variable in the 3rd statement, and then the body of the for loop is evaluated and compiled; else, if false, then the control is given to the next line in the “for-loop.”
• After the loop’s execution, the control is again passed to the conditional statement of the loop, and the 2nd step continues until the condition becomes false.

Example I of for-loop in C

#include <stdio.h>

int main() {

  float
  var;

  /* for loop execution */
  for (var = 10;
    var < 20;
    var =
    var +1) {
    printf("value of var: %d\n",
      var);
  }

  return 0;
}

Output

value of var: 10.00000

value of var: 11.00000

value of var: 12.00000

value of var: 13.00000

value of var: 14.00000

value of var: 15.00000

value of var: 16.00000

value of var: 17.00000

value of var: 18.00000

value of var: 19.00000

Example II of for-loop in C

#include <stdio.h>

int main() {
  int i;
  for (i = 1; i <= 3; i++) {
    printf("*\n");
  }
  return 0;
}

Output

*

*

*

Explanation- In the above program, a variable ‘i’ is initialized with a value equal to 1. The compiler will evaluate whether the condition given is true or not. If the condition is found true, then the body of “for loop” will get executed, and we will print the asterisk as output, and the value of the variable ‘i’ gets incremented by 1. The loop gets terminated once the condition becomes false.

Summary