C Exercises: Calculate the factorial of a given number

C For Loop: Exercise-15 with Solution

Write a C program to calculate the factorial of a given number.

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h>  // Include the standard input/output header file.

int  main(){
  int i, f = 1, num;  // Declare variables 'i' for loop counter, 'f' to store factorial, 'num' for user input.

  printf("Input the number : ");  // Print a message to prompt user input.
  scanf("%d", &num);  // Read the value of 'num' from the user.

  for(i = 1; i <= num; i++)  // Start a loop to calculate factorial.
      f = f * i;  // Calculate factorial.

  printf("The Factorial of %d is: %d\n", num, f);  // Print the calculated factorial.
   return 0;  // Indicate that the program has executed successfully.
}

Sample Output:

Input the number : 5                                                                                          
The Factorial of 5 is: 120 

Explanation:

for (i = 1; i <= num; i++)
  f = f * i;

In the above for loop, the variable i is initialized to 1, and the loop will continue as long as i is less than or equal to the value of variable 'num'. In each iteration of the loop, the value of variable 'f' is updated by multiplying it with the value of i using the assignment operator (*=).

The loop will increment the value of i by 1, and the process will repeat until the condition i<=num is no longer true.

Flowchart:

C Programming Code Editor:

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