Added RNG files

src/rng.c

@@ -0,0 +1,14 @@
+#include "rng.c"
+#include <stdlib.h>
+
+int rng_rand(int max){
+    max++;
+    int limit = RAND_MAX - (RAND_MAX % max),r;
+    while((r = rand()) >= limit);
+    return r % max;
+}
+
+int rng_roll(int droprate){
+    int r = rng_rand(droprate);
+    return (r==0)?1:0 ;
+}

src/rng.h

@@ -0,0 +1,8 @@
+#ifndef RNG_H
+#define RNG_H
+
+//Constants for probabilities
+
+int rng_rand(int max); //returns a random number in the range [0, max]
+int rng_roll(int droprate); //returns 1 with probability 1/droprate, else 0
+#endif