Page 108 - C-Language

Calculating the factorial of a number is a classic example of a recursive function.

Missing the Base Condition:

#include <stdio.h>

int factorial(int n)
{
return n * factorial(n - 1);
}

int main()
{
printf("Factorial %d = %d\n", 3, factorial(3));
return 0;
}

Typical output: Segmentation fault: 11

The problem with this function is it would loop infinitely, causing a segmentation fault — it needs a
base condition to stop the recursion.

Base Condition Declared:

#include <stdio.h>

int factorial(int n)
{
if (n == 1) // Base Condition, very crucial in designing the recursive functions.
{
return 1;
}
else
{
return n * factorial(n - 1);
}
}

int main()
{
printf("Factorial %d = %d\n", 3, factorial(3));
return 0;
}

Sample output

Factorial 3 = 6

This function will terminate as soon as it hits the condition n is equal to 1 (provided the initial value
of n is small enough — the upper bound is 12 when int is a 32-bit quantity).

Rules to be followed:

1. Initialize the algorithm. Recursive programs often need a seed value to start with. This is
accomplished either by using a parameter passed to the function or by providing a gateway

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