View difference between Paste ID: gDviLnqW and 95GwtFtP

 /* Changes relative to original post marked with comments
  * Original version at http://pastebin.com/95GwtFtP
-using namespace std;
+ */
 #include <iostream>
-int x;
+/* don't import whole namespace with 'using namespace std;'
-int y;
+ * just select the parts you need
-int d;
+ */
-string op;
+using std::cin;
-int answer;
+using std::cout;
 using std::endl;
 /* include string header because string is used
  * was previously included indirectly via iostream
-if (op == "Mult" || "mult" || "MULT"){
+ */
- d = x * y;
+#include <string>
-}else if (op == "Div" || "div" || "DIV"){
+using std::string;
- d = x / y;
+/* new dependency. See calc */
-}else if (op == "Add" || "add" || "ADD"){
+#include <cctype>
- d = x + y;
+using std::tolower;
-}else if (op == "Sub" || "sub" || "SUB"){
+
- d = x - y;
+/* got rid of all global variables */
-}else{
+
-cout << "Error";
+
-}
+  /* convert string to lower case to simplify string matching */
-return d;
+  for(int i = 0; i < op.length(); ++i)
     op[i] = tolower(op[i]);
   int d = 0;
-void printanswer() {
+  if (op == "mult")
-answer = calc(op, x, y);
+    d = x * y;
-cout << "Answer:" << answer;
+  else if (op == "div")
-cout << "Parameters: " << op << x << y;
+    d = x / y;
   else if (op == "add")
-
+    d = x + y;
   else if (op == "sub")
     d = x - y;
-cout << "What Operation? (Mult, Div, Sub, Add)";
+  else
-cin >> op;
+    cout << "Error";
-cout << "First Number?";
+
-cin >> x;
+  return d;
-cout << "Second Number?";
+
-cin >> y;
+
-printanswer();
+void printanswer(string op, int x, int y) {
   int answer = calc(op, x, y);
   cout << "Answer: " << answer;
   /* add missing whitespaces between values */
   cout << " Parameters: " << op << " " << x << " " << y;
   /* add a line break */
   cout << endl;
 }
 
 int main() {
   string op;
   int x, y;
   cout << "What Operation? (Mult, Div, Sub, Add)";
   cin >> op;
   cout << "First Number?";
   cin >> x;
   cout << "Second Number?";
   cin >> y;
   printanswer(op, x, y);
   /* add return statement. Value 0 signals normal termination */
   return 0;
 }