View difference between Paste ID: qGkk663u and m7PaahKr

 /**
-#include <math.h>
+* Fraction calculator
-using namespace std;
+* Initial version by 'zer0c00l' - http://pastebin.com/m7PaahKr
 * This version: Constantin 'morpha' Köpplinger
 * WaitForEnter() based on WaitForEnter() by Rachel 'Moosader' Morris
 */
-int numeratorOne;
+
-int denominatorOne;
+#include <string>
-int numeratorTwo;
+#include <functional>
-int denominatorTwo;
+
-int numeratorResult;
+int GCD(int n, int d, unsigned int max_depth = 1000)
-int denominatorResult;
+
-int operation;
+	if(n == 0)
 	{
 		return d;
-cout << "Enter the Numerator of the first fraction: ";
+
-while(true)
+	if(--max_depth == 0)
 	{
-	if(cin  >> numeratorOne)
+		return 0;
 	}
 	return GCD(d % n, n, max_depth);
 }
-	else
+
 void reduce(int &num, int &den)
-		cin.clear();
+
-		cin.ignore();
+	if(int gcd = GCD(num, den))
-		cout << "Sorry I didn't get that, please enter the numerator of the first fraction: ";
+
 		num /= gcd;
 		den /= gcd;
 	}
-cout << "Enter Denominator of the first fraction: ";
+
-while(true)
+
 template <typename TYPE>
-	if(cin >> denominatorOne)
+void input(TYPE &to, std::function<bool (TYPE data, bool valid_input)> validator)
 {
-		if(denominatorOne == 0)
+	do
 	{
-			cout << "Sorry the denominator can not be zero, please enter a non-zero integer: ";
+		std::cin.sync();
 		std::cin.clear();
-		else
+		std::cin >> to;
 	} while(std::cin.fail() || !validator(to, std::cin.good()));
-			break;
+
 
 template <typename TYPE>
-	else
+void input(TYPE &to, std::string const &onError)
 {
-		cin.clear();
+	do
-		cin.ignore();
+
-		cout << "Sorry I didn't get that, please enter the denominator of the first fraction: ";
+		std::cin.sync();
 		std::cin.clear();
 		std::cin >> to;
 		if(std::cin.fail())
-cout << "Enter the Numerator of the second fraction: ";
+
-while(true)
+			std::cout << onError;
 			continue;
-	if(cin  >> numeratorTwo)
+
 	} while(false);
 }
 
-	else
+void WaitForEnter()
 {
-		cin.clear();
+	std::cin.sync();
-		cin.ignore();
+	std::cin.clear();
-		cout << "Sorry I didn't get that, please enter the numerator of the second fraction: ";
+	while(std::cin.get() != '\n'){}
 }
 
 int main()
-cout << "Enter Denominator of the second fraction: ";
+
-while(true)
+	int numeratorOne;
 	int denominatorOne;
-	if(cin >> denominatorTwo)
+	int numeratorTwo;
 	int denominatorTwo;
-		if(denominatorTwo == 0)
+	int numeratorResult;
 	int denominatorResult;
-			cout << "Sorry the denominator can not be zero, please enter a non-zero integer: ";
+	char operation;
 
-		else
+
 	std::cout << "Enter the Numerator of the first fraction: ";
-			break;
+	input<int>(numeratorOne, std::string("Sorry I didn't get that, please enter the numerator of the first fraction: "));
 
 	std::cout << "Enter Denominator of the first fraction: ";
-	else
+	input<int>(denominatorOne, [](int denom, bool valid) -> bool
 	{
-		cin.clear();
+		if(!valid)
-		cin.ignore();
+
-		cout << "Sorry I didn't get that, please enter the denominator of the second fraction: ";
+			std::cout << "Sorry I didn't get that, please enter the denominator of the first fraction: ";
 			return false;
 		}
 		if(denom == 0)
-cout << "Please select which operation you would like to do. "
+
-	 << "\n" << "1-Add"
+			std::cout << "Sorry the denominator can not be zero, please enter a non-zero integer: ";
-	 << "\n" << "2-Subtract"
+			return false;
-	 << "\n" << "3-Multiply"
+
-	 << "\n" << "4-Divide"
+		return true;
-	 << "\n" << "Select from the above list: ";
+	});
 
-while(true)
+	std::cout << "Enter the Numerator of the second fraction: ";
 	input<int>(numeratorTwo, std::string("Sorry I didn't get that, please enter the numerator of the second fraction: "));
-	if(cin >> operation)
+
 	std::cout << "Enter Denominator of the second fraction: ";
-		if(operation<1 || operation >4)
+	input<int>(denominatorTwo, [](int denom, bool valid) -> bool
 	{
-			cout << "Sorry please select a number from 1-4: ";
+		if(!valid)
 		{
-		else
+			std::cout << "Sorry I didn't get that, please enter the denominator of the second fraction: ";
 			return false;
-			break;
+
 		if(denom == 0)
 		{
-	else
+			std::cout << "Sorry the denominator can not be zero, please enter a non-zero integer: ";
 			return false;
-		cin.clear();
+
-		cin.ignore();
+		return true;
-		cout << "Sorry I didn't get that, please enter a number between 1-4: ";
+	});
 
 	std::cout << "Please select which operation you would like to do. "
 		 << "\n" << "1 - Add      [+]"
-//Add
+		 << "\n" << "2 - Subtract [-]"
-if (operation == 1)
+		 << "\n" << "3 - Multiply [*, x]"
 		 << "\n" << "4 - Divide   [/, :]"
-numeratorResult = (numeratorOne * denominatorTwo + numeratorTwo * denominatorOne);
+		 << "\n" << "Select from the above list: ";
-denominatorResult = (numeratorOne * denominatorTwo);
+
-cout << numeratorOne << "/" << denominatorOne
+	input<char>(operation, [](char denom, bool valid) -> bool
-	 << " + "
+
-	 << numeratorTwo << "/" << denominatorTwo
+		if(!valid)
-	 << " = "
+
-	 << numeratorResult << "/" << denominatorResult << "\n";
+			std::cout << "Sorry please select a number from 1-4 (or the appropriate sign): ";
 			return false;
 		}
-//Subtract
+		if(std::string("1234+-/*:x").find(denom) == std::string::npos)
-if (operation ==2)
+
 			std::cout << "Sorry I didn't get that, please select a number from 1-4 (or the appropriate symbol): ";
-numeratorResult = (numeratorOne * denominatorTwo - numeratorTwo * denominatorOne);
+			return false;
-denominatorResult = (numeratorOne * denominatorTwo);
+
-cout << numeratorOne << "/" << denominatorOne
+		return true;
-	 << " - "
+	});
-	 << numeratorTwo << "/" << denominatorTwo
+
-	 << " = "
+	switch(operation)
-	 << numeratorResult << "/" << denominatorResult << "\n";
+
 		//Add
 		case '1':
-//Multiply
+			operation = '+';
-if(operation == 3)
+		case '+':
 			numeratorResult = ((numeratorOne * denominatorTwo) + (numeratorTwo * denominatorOne));
-numeratorResult = numeratorOne * numeratorTwo;
+			denominatorResult = (denominatorOne * denominatorTwo);
-denominatorResult = denominatorOne * denominatorTwo;
+
-cout << numeratorOne << "/" << denominatorOne
+
-	 << " x "
+		//Subtract
-	 << numeratorTwo << "/" << denominatorTwo
+		case '2':
-	 << " = "
+			operation = '-';
-	 << numeratorResult << "/" << denominatorResult << "\n";
+		case '-':
 			numeratorResult = ((numeratorOne * denominatorTwo) - (numeratorTwo * denominatorOne));
 			denominatorResult = (denominatorOne * denominatorTwo);
-//Divide
+
-if(operation == 4)
+
 		//Multiply
-numeratorResult = numeratorOne * denominatorTwo;
+		case '3':
-denominatorResult = denominatorOne * numeratorTwo;
+			operation = 'x';
-cout << numeratorOne << "/" << denominatorOne
+		case '*':
-	 << " / "
+		case 'x':
-	 << numeratorTwo << "/" << denominatorTwo
+			numeratorResult = (numeratorOne * numeratorTwo);
-	 << " = "
+			denominatorResult = (denominatorOne * denominatorTwo);
-	 << numeratorResult << "/" << denominatorResult << "\n";
+
 
 		//Divide
-system("PAUSE");
+		case '4':
 			operation = '/';
 		case '/':
 		case ':':
 			numeratorResult = numeratorOne * denominatorTwo;
 			denominatorResult = denominatorOne * numeratorTwo;
 		break;
 	}
 
 	reduce(numeratorResult, denominatorResult);
 
 	std::cout << numeratorOne << "/" << denominatorOne
 	<< " " << operation << " "
 	<< numeratorTwo << "/" << denominatorTwo
 	<< " = "
 	<< numeratorResult << "/" << denominatorResult << "\n";
 
 	std::cout << "Press RETURN to quit.";
 	WaitForEnter();
 
 	return 0;
 }