## How to use find out the factorial of a number in C language

### program to use find out the factorial of a number in C language

``````
#include <stdio.h>
long int factorial(int n);
int main()
{
int num;
printf("Enter a number : ");
scanf("%d",&num);
if(num<0)
printf("No factorial of negative number\n");
else
printf("Factorial of %d is %ld\n",num,factorial(num));
return 0;
}
long int factorial(int n)
{
int i;
long int fact=1;
if(n==0){
return 1;
}
for(i=n; i>1; i--){
fact*=i;
}

return fact;
}
``````
``` ```

### output

``````
Enter a number : 8
Factorial of 8 is 40320
``````

## How to use whether a number is even or odd in C language

### program to use whether a number is even or odd in C language

``````
#include <stdio.h>
void find(int n);
int main()
{
int num;
printf("Enter a number : ");
scanf("%d",&num);
find(num);
return 0;
}
void find (int n)
{
if(n%2==0)
printf("%d is even\n",n);
else
printf("%d is odd\n",n);
}
``````
``` ```

### output

``````
Enter a number : 444
444 is even
``````

## How to use function find the sum of two numbers in C language

### program to use function find the sum of two numbers in C language

``````
#include <stdio.h>
int sum(int x,int y)
{
int s;
s=x+y;
return s;
}
int main()
{
int a,b,s;
printf("Enter value for a and b : ");
scanf("%d %d",&a,&b);
s=sum(a,b);
printf("sum of %d and %d is %d\n",a,b,s);
return 0;
}
``````
``` ```

### output

``````
Enter value for a and b : 12
6
sum of 12 and 6 is 18
``````

## How to use find the sum of two numbers in C Language

``````
#include <stdio.h>
int sum(int x, int y) /*function definition*/
{
int s;
s = x + y;
rextturn s;
}
int main(void)
{
int a, b, s;
printf("Enter values for a and b : ");
scanf("%d %d", &a, &b);
s = sum(a, b); /*function call*/
printf("Sum of %d and %d is %d\n", a, b, s);
return 0;
}
``````
``` ```

### Output

``````
Enter value for a and b :12
6
Sum of 12 and 6 is 18
``````
``` ```