add support for negative exponents

src/exponent.c

@@ -10,4 +10,12 @@ int expI(unsigned int e, int num){
         }
         return prod;
     }
+}
+
+float expIN(int e, int num){
+    if(e>0){
+        return (float) expI(e, num);
+    }else{
+        return  1.0 / (float) expI(e, num);
+    }
 }

src/exponent.h

@@ -2,5 +2,6 @@
 #define EXPONENT_H
 
 int expI(unsigned int e, int num);
+float expIN(int e, int num);
 
 #endif // exponent.h