C++编程练习||创建一个名为Rational的类，进行分数运算。

题目：创建一个名为Rational的类，进行分数运算。

创建一个名为Rational的类，进行分数运算。用整数变量表示类的private数据－numerator（分子）和denominator（分母）。提供一个带默认值的构造函数，并且它应该以简化的形式保存分数。

例如分数2/4应在对象中保存为numerator为1，denominator为2的形式。

对下列任务，提供完成它们的public成员函数：

a）两个Rational值相加，结果应以简化的形式保存。

b）两个Rational值相减，结果应以简化的形式保存。

c）两个Rational值相乘，结果应以简化的形式保存。

d）两个Rational值相除，结果应以简化的形式保存。

e）以a/b形式打印Rational值，其中a是分子，b是分母。

f）以浮点数的形式打印Rational值。

主函数分别输入两个分数的分子和分母，以及将要进行的运算。分别以分数形式和小数形式输出运算结果。

注意，负分数输出时负号后有一个空格，小数的负号后没有空格。

#include <iostream>
#include <iomanip>
#include <cmath>

using namespace std;

class Rational {
	
	private:
		void simplify() {
			int flag = abs(this->numerator);
			while(flag > 1) {
				if((this->numerator % flag) == 0 && (this->denominator % flag) == 0) {
					this->numerator /= flag;
					this->denominator /= flag;
				}
				flag--;
			} 
		}
	
	public:
		
		int numerator;
		int denominator;
		
		Rational(int c_num = 0, int c_den = 0) {
			
			if ((c_num > 0 && c_den > 0) || (c_num < 0 && c_den < 0)) {
				this->numerator = abs(c_num);
				this->denominator = abs(c_den);
			} else {
				this->numerator = -abs(c_num);
				this->denominator = abs(c_den);
			}
			
			c_num = abs(c_num);
			while(c_num > 1) {
				if((this->numerator % c_num) == 0 && (this->denominator % c_num) == 0) {
					this->numerator /= c_num;
					this->denominator /= c_num;
				}
				c_num--;
			}
		}
		
		void add(Rational a, Rational b) {
			this->numerator += (a.numerator * b.denominator + a.denominator * b.numerator);
			this->denominator += (a.denominator * b.denominator);
			this->simplify();
		}

		void minus(Rational a, Rational b) {
			this->numerator += (a.numerator * b.denominator - a.denominator * b.numerator);
			this->denominator += (a.denominator * b.denominator);
			this->simplify();
		}

		void multi(Rational a, Rational b) {
			this->numerator += (a.numerator * b.numerator);
			this->denominator += (a.denominator * b.denominator);
			this->simplify();
		}

		void divide(Rational a, Rational b) {
			this->numerator += (a.numerator * b.denominator);
			this->denominator += (a.denominator * b.numerator);
			this->simplify();
		}

		void printFormal() {
			cout << numerator << "/" << denominator << endl;
		}
		
		void printBoth() {
			cout << "the Formal format of the rational is : " << numerator << "/" << denominator << endl;
			cout << "the Fixed format of the rational is : " << setprecision(2) << fixed << (double)numerator/denominator << endl;
		}

};

int main() {
	int firstN,firstD,secondN,secondD;
	char op;

//    cout<<"Please input the numerator of first Rational: ";
	cin>>firstN;
//    cout<<"Please input the denominator of first Rational: ";
	cin>>firstD;
//    cout<<"Please input the numerator of second Rational: ";
	cin>>secondN;
//    cout<<"Please input the denominator of second Rational: ";
	cin>>secondD;


	Rational r1(firstN,firstD),r2(secondN,secondD),r3;


	cin>>op;

	cout<<"the Formal format of the first rational is : ";
	r1.printFormal();
	cout<<"the Formal format of the second rational is : ";
	r2.printFormal();
	cout<<endl;

	switch(op) {
		case '+' :
			r3.add(r1,r2);
			r3.printBoth();
			break;
		case '-' :
			r3.minus(r1,r2);
			r3.printBoth();
			break;
		case '*':
			r3.multi(r1,r2);
			r3.printBoth();
			break;
		case '/':
			r3.divide(r1,r2);
			r3.printBoth();
			break;
		default:
			cout<<"Invalid operator!";
	}

	return 0;
}

运行结果：