Expanded arithmetic addition by double calculation

src/arithmeticAddition.c

@@ -11,3 +11,9 @@ int* addition_integer(int num1, int num2) {
     *result = num1 + num2;
     return result;
 }
+
+double* addition_double(double num1, double num2) {
+    double* result = malloc(sizeof(double));
+    *result = num1+num2;
+    return result;
+}

src/arithmeticAddition.h

@@ -3,4 +3,6 @@
 
 int* addition_integer(int, int);
 
+double* addition_double(double, double);
+
 #endif //THEADMIRALS_ARITHMETICADDITION_H