compute factorial with int, uint, float, double and gmp

factorial.c

@@ -1,30 +1,66 @@
 #include <stdio.h>
-#include<stdlib.h>
+#include <stdlib.h>
+#include <gmp.h>
+#include <assert.h>
 
-double factorial(int n) {
-   double f = 1;
+void gmpfactorial(mpz_t result, int n) {
+   mpz_set_ui(result,1);
    for(int i=1; i < n+1; i++)
-      f = f*(double)i;
+      mpz_mul_ui(result,result,i);
+}
+
+int intfactorial(int n) {
+   int f = 1;
+   for(int i=1; i < n+1; i++)
+      f = f*i;
+   return f;
+}
+
+uint uintfactorial(int n) {
+   uint f = 1;
+   for(int i=1; i < n+1; i++)
+      f = f*(uint)i;
    return f;
 }
 
-float ffactorial(int n) {
+float floatfactorial(int n){
    float f = 1;
    for(int i=1; i < n+1; i++)
       f = f*(float)i;
    return f;
 }
 
+double doublefactorial(int n) {
+   double f = 1;
+   for(int i=1; i < n+1; i++)
+      f = f*(double)i;
+   return f;
+}
+
 int main(int argc, char *argv[]) {
   int n;
-  double f;
-  float ff;
+  double dfac;
+  float ffac;
+  int ifac;
+  uint uifac;
+  mpz_t mfrac;
+  mpz_init(mfrac);
+
   if (argc > 1) 
     n = atoi( argv[1] );
   else
     n = 1;
-  f = factorial(n);
-  ff = ffactorial(n);
-  printf("%.0f\t%.0lf\n", ff, f);
+
+  dfac = doublefactorial(n);
+  ffac = floatfactorial(n);
+  ifac = intfactorial(n);
+  uifac = uintfactorial(n);
+  gmpfactorial(mfrac, n); 
+
+  printf("%d\t%d (%d bits)\t%u (%d bits)\t%.0f (%d bits)\t%.0lf (%d bits)\t", (int) n, ifac, 8*(int) sizeof(int), uifac, 8*(int) sizeof(uint), ffac, 8*(int) sizeof(float), dfac, 8*(int) sizeof(double));
+  gmp_printf ("%Zd", mfrac);
+  printf(" (%d bits)\n", 8*(int) sizeof(mfrac));
+
+  mpz_clear(mfrac);
   return 0;
 }