#include<stdio.h>
long int fact(int n);
long int Ifact(int n);
main( )
{
int num;
printf("Enter a number : ");
scanf("%d", &num);
if(num<0)
printf("No factorial for negative number\n");
else
printf("Factorial of %d is %ld\n", num, fact(num) );
if(num<0)
printf("No factorial for negative number\n");
else
printf("Factorial of %d is %ld\n", num, Ifact(num) );
}/*End of main()*/
/*Recursive*/
long int fact(int n)
{
if(n == 0)
return(1);
return(n * fact(n-1));
}/*End of fact()*/
/*Iterative*/
long int Ifact(int n)
{
long fact=1;
while(n>0)
{
fact = fact*n;
n--;
}
return fact;
}/*End of ifact()*/Enter a number : 5
Factorial of 5 is 120
Factorial of 5 is 120
Press any key to continue . . .
/*Recursive*/
long int fact(int n)
{
if(n == 0)
return(1);
return(n * fact(n-1));
}/*End of fact()*/
/*Iterative*/
long int Ifact(int n)
{
long fact=1;
while(n>0)
{
fact = fact*n;
n--;
}
return fact;
}/*End of ifact()*/
First read the algorithm, then study the program code line by line. After that, compare the code with the output and finally go through the explanation. This approach helps learners understand both the logic and the implementation properly.
After understanding this example, try to rewrite the same program without looking at the code. Then change some values or logic and run it again. This helps improve confidence and keeps learners engaged on the page for longer.