Calculating factorial of large numbers in C
algorithm, c
Solution
No standard C data type will accurately handle numbers as large as 100!. Your only option if to use arbitrary precision integer arithmetic, either through a library or done by yourself.
If this is just some hobby project, I'd suggest trying it yourself. It's kind of a fun exercise. If this is work-related, use a pre-existing library.
The largest C data type you'll normally get is a 64-bit integer. 100! is in the order of 10157, which takes at least 525 bits to store accurately as an integer.
Problem
In my C code, I want to calculate the factorial for numbers in the range 1 to 100. For small numbers, the function works, but for bigger numbers (for example 100!) it returns incorrect result. Is there any way to handle factorial of large numbers in C? The compiler I'm using is gcc v4.3.3. My code is as follows: ``` #include <stdio.h> #include <math.h> double print_solution(int); int main(void) { int no_of_inputs, n; int ctr = 1; scanf("%d",&no_of_inputs); //Read no of inputs do { scanf("%d",&n); //Read the input printf("%.0f\n", print_solution(n)); ctr++; } while(ctr <= no_of_inputs); return 0; } double print_solution(int n) { if(n == 0 || n == 1) return 1; else return n*print_solution(n-1); } ```