Add main.c for calculator program

calculator/main.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "operations.h"
+
+int main(){
+    printf("Welcome to the world's most advanced calculator!\n");
+    printf("After years of research and development, we are proud to welcome you to our new and improve calculator.\n");
+
+    // Prompt user to select a choice.
+    printf("First, choose an operation. Choose one of the following options:\n");
+    printf("+ for addition\n");
+    printf("* for multiplication\n");
+    printf("/ for division\n");
+    printf("- for subtraction\n");
+
+    char choice; 
+    scanf ("%c", &choice);
+
+    // Prompt user to enter numbers. 
+    int a;
+    int b;
+    printf("Now you will need to enter two numbers: a and b.\n");
+    printf("Please enter a value for a: \n");
+    scanf("%d", &a);
+
+    printf("Please enter a value for b: \n");
+    scanf("%d", &b);
+
+    // Evaluate operation based on user's choice.
+    int result; 
+    switch (choice){
+      case '+':
+        result = add(a, b);
+      case '-':
+        result = subtract(a, b);
+      case '*':
+        result = multiply(a, b);
+      case '/':
+        result = divide(a, b);
+    }
+
+    printf("The result of your operation is %d\n", result); 
+
+    return 0;
+
+}