C++快速入门 课件源码讨论之重载<<操作符
#include <iostream>#include <string>
#include <stdlib.h>
class Rational
{
public:
Rational(int num,int denom);
Rational operator+(Rational rhs);
Rational operator-(Rational rhs);
Rational operator*(Rational rhs);
Rational operator/(Rational rhs);
private:
void normalize();
int numerator;
int denominator;
friend std::ostream& operator<<(std::ostream& os, Rational f);
};
Rational::Rational(int num, int denom)
{
numerator = num;
denominator = denom;
normalize();
}
void Rational::normalize()
{
if (denominator<0)
{
numerator = -numerator;
denominator = -denominator;
}
int a = abs(numerator);
int b = abs(denominator);
while (b>0)
{
int t = a%b;
a = b;
b = t;
}
numerator /= a;
denominator /= a;
}
Rational Rational::operator+(Rational rhs)
{
int a = numerator;
int b = denominator;
int c = rhs.numerator;
int d = rhs.denominator;
int e = a*b + c*d;
int f = b*d;
return Rational(e, f);
}
Rational Rational::operator-(Rational rhs)
{
rhs.numerator =- rhs.numerator;
return operator+(rhs);
}
Rational Rational::operator*(Rational rhs)
{
int a = numerator;
int b = denominator;
int c = rhs.numerator;
int d = rhs.denominator;
int e = a*c;
int f = b*d;
return Rational(e, f);
}
Rational Rational::operator/(Rational rhs)
{
int t = rhs.numerator;
rhs.numerator = rhs.denominator;
rhs.denominator = t;
return operator*(rhs);
}
std::ostream& operator<<(std::ostream& os, Rational f);
int main()
{
Rational f1(2, 16);
Rational f2(7, 8);
std::cout << f1 << "+"<< f2 << "=" << (f1 + f2) << "\n";
std::cout << f1 << "-" << f2 << "=" << (f1- f2) << "\n";
std::cout << f1 << "*" << f2 << "=" << (f1 *f2) << "\n";
std::cout << f1 << "/" << f2 << "=" << (f1 /f2)<< "\n";
return 0;
}
std::ostream& operator<<(std::ostream& os, Rational f)
{
os << f.numerator << "/" << f.denominator;
return os;
}
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