p20 and a minor change in p11

p20.c

@@ -0,0 +1,46 @@
+
+/*
+ * http://projecteuler.net
+ * 
+ * Projecteuler - Problem 20
+ * ------------------------
+ * 2010-05-17 Henrik Hautakoski
+ *
+ * easy with a good lib for doing arbitrary-precision arithmetic
+ */
+
+#include <stdio.h>
+#include <malloc.h>
+#include <gmp.h>
+
+char* fak(int n) {
+
+    mpz_t v;
+    mpz_init(v);
+    mpz_fac_ui(v, n);
+    return mpz_get_str(NULL, 10, v);
+}
+
+int sum(char *n) {
+    
+    int num = 0;
+    
+    for(; *n != '\0'; n++)
+        num += (*n) - 0x30;
+        
+    return num;
+}
+
+int main() {
+
+    char *n = fak(100);
+
+    if (n == NULL)
+        return 1;
+
+    printf("%i\n", sum(n));
+
+    free(n);
+
+    return 0;
+}