C programme for factorial using while loop nd for loop

using while loop                                                

#include <stdio.h>
#include<conio.h>
void main()
{
int n,i=1,fact=1;
printf("enter a number");
scanf(""%d",&n);
while(i<=n)
{
fact=fact*i;
i=i+1;
}
printf("%d",&fact);
getch();
}

using for loop

#include <stdio.h>

#include<conio.h>

void main()

{

int n,i=1,f=1;

printf("enter a number");

scanf(""%d",&n);

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

f=f*i;

printf("\n factorial of %d is %d \n",n,f);

getch();

}

C programme for multiplication of digits

#include <stdio.h>

#include <conio.h>

void main()

{

int prod=1,n,a;

clrscr();

printf("enter a number");

scanf("%d",&n);

while(n>0)

{

a=n%10;

prod=prod*a;

n=n/10;

}

printf("%d",&prod);

getch();

}

C programme for addition of sum of digits

#include <stdio.h>

#include <conio.h>

void main()

{

int a,sum=0,n;

clrscr();

printf("enter a number");

scanf("%d",&n);

while(n>0)

{

a=n%10;

sum=sum+a;

n=n/10;

}

printf("%d",&sum);

getch();

}

C programme to reverse a number using while loop

#include <stdio.h>
#include <conio.h>
void main()
{
int n,mod,rev=0;
clrscr();
printf("enter a number");
scanf("%d",&n);
while(n>0)
{
mod=n%10;
rev=rev*10+mod;
n=n/10;
}
printf("%d",&rev);
getch();
}