Question

我对我的fractionType类有疑问。我正在为分配编码，分配要求我重载基本算术运算符（+， - ，/，*）逻辑运算符（==，＆lt;，＆gt;，=＆lt;，=＆gt;）和系统运营商（＆lt;＆lt;，＆gt;＆gt;）到目前为止，我有系统操作员，以及乘法和除法运算符。当我测试+和 - 运算符时，我的问题出现了。我的输入被硬编码为2/4和1/8，但我的输出是3/8。这不对。

我的代码来自fractionType.cpp

#include <iostream>
#include "fractionType.h"

fractionType::fractionType(){
}
fractionType::fractionType(int a, int b) {
  numerator = a;
  denominator = b;
}
fractionType fractionType::operator+(fractionType fraction) {
  fractionType anotherFraction;
  if (denominator = fraction.denominator) {

      anotherFraction.numerator = numerator + fraction.numerator;

      anotherFraction.denominator = denominator;
  }
if (denominator != fraction.denominator) {
    anotherFraction.numerator = ((numerator) * (fraction.denominator)) +         ((fraction.numerator) * (denominator));

    anotherFraction.denominator = denominator * fraction.denominator;
}
return anotherFraction;
}
fractionType fractionType::operator-(fractionType fraction) {

fractionType anotherFraction;

if (denominator = fraction.denominator) {

    anotherFraction.numerator = numerator - fraction.numerator;

    anotherFraction.denominator = denominator;
}
else {
    anotherFraction.numerator = (numerator * fraction.denominator) - (fraction.numerator * fraction.denominator);

    anotherFraction.denominator = denominator * fraction.denominator;
}

return anotherFraction;


}

我的代码来自fractionType.h

#include <iostream>

class fractionType {
public: 
  fractionType(int a, int b);
  fractionType();
  fractionType operator*(fractionType fraction);
  fractionType operator/(fractionType fraction);
  fractionType operator+(fractionType fraction);
  fractionType operator-(fractionType fraction);
  friend std::ostream& operator<<(std::ostream& out, const fractionType &fraction) {
    out << fraction.numerator << '/' << fraction.denominator;
    return out;
}
friend std::istream& operator>> (std::istream& in, fractionType &fraction) {
    char c;
    in >> fraction.numerator >> c >> fraction.denominator;
    return in;
}
private:
int numerator, denominator;
};
#endif FRACTIONTYPE_H

和我的source.cpp

#include <iostream>
#include "fractionType.h"

int main() {
  fractionType aFraction(2, 4);
  fractionType bFraction(1, 8);
  fractionType cFraction;
  cFraction = aFraction + bFraction;
  std::cout << cFraction << std::endl;
  system("PAUSE");
}

我切断了我的操作员*和操作员/，因为它们正常工作。我不知道自己做错了什么，在发布这个问题之前，我一遍又一遍地重复数学。是因为我没有使用指针吗？一个常量？或者是不同的东西？在此先感谢您的帮助！

Answer 1

这一行错了：

if (denominator = fraction.denominator) {

必须是

if (denominator == fraction.denominator) {

如果启用了警告，clang和gcc会告诉您，例如：

main.cpp:32:19: warning: using the result of an assignment as a condition without parentheses [-Wparentheses]

  if (denominator = fraction.denominator) {

      ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

live example

如果您更正了上述错误，则代码可以正常运行：

<强>输出

20/32

live example

如何修复我的小数类的重载+运算符的输出？

1 个答案: