How to convert a while loop to a for loop in c

The basic structure of for loop is as following

for(initialization; condition; adjustment){
        statement(s);
      }

So the fo loop has four parts,

1. Initialization: We need to assign a value for the control variable.
2. condition: We have to use a conditional expression here. The compiler execute/iterate the for loop until it get 0 or false
3. adjustment: Adjust the control variable (by increment or decrement ) so that the condition get 0 or false
4. statement(s): Any type of simple or compound statement(s)

The basic structure of while loop is as following

while(condition){
        statement(s);
      }

We can see that the while loop has only two parts

1. Condition
2. statement(s)

So if we wish to use the while loop as the for loop we need to construct it as the following

initialization;
while( condition){
        statement(s);
      adjustment;
       }

Now lets see a program using both for loop and while loop. See the factorial finding program using both for loop and while loop

#include<stdio.h>
int main(void){

int count;

printf("Using for loop\n\n");
for(count = 1;count<=5; count++){
        printf(" \t count is %d\n",count);
        }


printf("\n Using for loop\n\n");
count = 1;
while(count<=5 ){
        printf("\t count is %d\n",count);
        count++;
        }

return 0;
}

Factorial program in c using for loop, while loop and function.

Wikipedia define factorial as following

In mathematics, the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n.

Math is Fun gives the following definition

The factorial function (symbol: !) means to multiply a series of descending natural numbers.

Example
4! = 4 × 3 × 2 × 1 = 24
7! = 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5040
1! = 1 0! = 1, because the following reason.

We can rearrange one thing only one way, as 0 is also an entity so we can rearrange it in one way.
Also we can prove it mathematically with the help of Combination
Let us consider n is the number of different people, if we choose a team consisting with n people then we can only choose it one time, so

Now lets start coding using for loop

#include<stdio.h>
int main(){

    int n,i;
    float fact=1;
    printf("Enter your n\n");
    scanf("%d",&n);
    
    if(n <0 ) printf("\aPlease enter a positive number\n");
    else if((n == 1) || (n == 0)){
        printf("\aThe factorial is 1\n");
    }
   else{
            for(i=1;i<=n;i++){
            fact =fact*i;
            }
        printf("\aThe factorial is %.2f\n",fact);
       }

    return 0;
}

Using while loop

#include<stdio.h>

int main(){

    int n,i=1;
    float fact=1;
    printf("Enter your n\n");
    scanf("%d",&n);
    if(n <0 ) printf("\aPlease enter a positive number\n");
    else if((n == 1) || (n == 0)){
        printf("\aThe factorial is 1\n");
    }
   else{
           while(i<=n){
            fact =fact*i;
                i++;
            }
          printf("\aThe factorial is %.2f\n",fact);
       }

    return 0;
}

Using user defined function

#include<stdio.h>

float factorial( int n){
    if((n == 1) || (n == 0) ) return 1;
    else return n*factorial(n-1);
}

int main(){

    int n;
    printf("Enter your n\n");
    scanf("%d",&n);
    if(n <0 ) printf("\aPlease enter a positive number\n");
    else  printf("\aThe factorial is %.2f\n",factorial(n));

    return 0;
}