fix structure errors

project_cpp/functions.cpp

@@ -0,0 +1,19 @@
+#include <iostream>
+#include <math.h>
+
+int add (int a, int b) {
+    return a + b;
+}
+
+
+int multiple (int a, int b) {
+    return a * b;
+}
+
+int substraction (int a, int b) {
+    return a - b;
+}
+
+int devide (int a, int b) {
+    return round(a / b);
+}

project_cpp/main.cpp

@@ -1,22 +1,23 @@
 #include <iostream>
 #include <math.h>
+#include "./functions.cpp"
 
-int add (int a, int b) {
-    return a + b;
-}
+// int add (int a, int b) {
+//     return a + b;
+// }
 
 
-int multiple (int a, int b) {
-    return a * b;
-}
+// int multiple (int a, int b) {
+//     return a * b;
+// }
 
-int substraction (int a, int b) {
-    return a - b;
-}
+// int substraction (int a, int b) {
+//     return a - b;
+// }
 
-int devide (int a, int b) {
-    return round(a / b);
-}
+// int devide (int a, int b) {
+//     return round(a / b);
+// }
 
 int main () {
     std::cout << "ADD: " << add(4, 5) << "\n";

tests/tests.cpp

@@ -1,5 +1,5 @@
 #include <iostream>
-#include "../project_cpp/main.cpp"
+#include "../project_cpp/functions.cpp"
 
 int add_test() {
     if(add(4, 5) != 9) {