Added main function ability executing first part of calculator features

src/main.c

@@ -1,4 +1,17 @@
 #include <stdio.h>
+#include <string.h>
+#include "operationHandler.h"
+
+char buffer[100];
 
 int main() {
+    printf("Please enter the id of a specific operation...\n1. addition\n2. subtraction\n3. multiplication\n4. division\n");
+    int input;
+    scanf("%d", &input);
+    if(!checkOperationInput(input)) {
+        printf("Invalid operation id\n");
+        return 0;
+    }
+    printf("\nPlease enter the first and the second number separated by a space...\n");
+
 }