/*factirial*/
 
#include<stdio.h>
#include<conio.h>
void main()
{
int n,s=1,i;
clrscr();
printf("enter n ");
for(i=1;i<n;i++)
{
scanf("%d",&n);
}
for(i=1;i<n;i++)
{
s=s*i;
}
printf("factorial is %d",s);
getch();
}

/*factirial*/
 
#include<stdio.h>
#include<conio.h>
void main()
{
int n,s=1,i; /* n = unknown garbage, s = 1, i = unknown garbage */
clrscr();
printf("enter n ");
for(i=1;i<n;i++) /* Initially loop as long as i is less than n. what was in n?. Garbage! anything can happens */
{
scanf("%d",&n); /* user set n to some integer, let's say as an example integer 4 */ 
}
for(i=1;i<n;i++)  /* Initially i= 1, n = 4; 1 < 4? Yes, execute block */ /* Will do 3 times */
{
s=s*i; /*first time s = 1 * 1 = 1 */ /* second time s = 1 * 2 = 2 */ /* third time s = 2 * 3 = 6 */
}
printf("factorial is %d",s); /* factorial is 6 */ /* This line has to be inside the loop to display each value */
getch();
}