refactoring: used length for indexing instead of index

src/conversionOfNumbers/conversionOfNumbers.c

@@ -6,14 +6,13 @@ char* convertIntToBinaryStr(int input){
     int length = 2;
     int rest;
     char* result = (char*)malloc(sizeof(char) * length + 1);
-    int index = length - 1;
+    result[length] = '\0';
     do{
         rest = input % 2;
         input /= 2;
-        if(rest == 1) result[index] = '1';
-        if(rest == 0) result[index] = '0';
-        index--; 
+        if(rest == 1) result[length - 1] = '1';
+        if(rest == 0) result[length - 1] = '0';
+        length--; 
     }while(input != 0);
-    result[length] = '\0';
     return result;
 }