A fun little shortcut I created to reduce fractions... until I found the Math>Frac function on my TI-84.

reducefraction.cpp

#include<iostream>
#include<cmath>

using namespace std;

bool is_integer(float k)
{
	return std::floor(k) == k;
}

int main()
{
	cout << "Reduce a fraction!" << endl;
	cout << "Enter the numerator:";

	double number1 = 0;
	cin >> number1;

	cout << "Enter the denominator:";

	double number2 = 0;
	cin >> number2;

	cout << "------------------------------------" << endl;

	double number1HighestFactor = number1 / 2;
	double number2HighestFactor = number2 / 2;

	double highestFactor = (number1HighestFactor > number2HighestFactor) ? number1HighestFactor : number2HighestFactor;

	int factorOfNumber1 = 0, factorOfNumber2 = 0;

	for (int i = 1; i < (highestFactor + 1); i++)
	{
    	// We only want to print out common factors
		if (is_integer(number1/i) && is_integer(number2/i))
		{
			factorOfNumber1 = number1 / i;
			factorOfNumber2 = number2 / i;

			cout << "Common factor of " << i << ": " << "(" << number1 << ")" << factorOfNumber1 << " (" << number2 << ")" << factorOfNumber2 << endl;
		}
	}

	cout << "------------------------------------" << endl;

	cout << "The simplest form for " << number1 << "/" << number2 << " is " << factorOfNumber1 << "/" << factorOfNumber2 << endl;

	cout << endl;
	system("pause");
	return 0;
}