c++实现简单计算器

来源：互联网发布：轮毂拉丝机编程编辑：程序博客网时间：2024/05/16 06:58

帮一个同学写的，非计算机类专业，应付交差，也没什么功能，两个数的加减乘除运算，以及三角函数的运算。要求用到模板、运算符重载和异常处理。

一直以来都是用的java，没怎么用过c++，就当是复习了一下c++语法。

代码如下：

#include<iostream>#include<string>#include<cmath>#include<cstdlib>using namespace std;//四则运算template <class T> class ElementaryArithmetic{private:    T result;    T operand1, operand2;    char operators;public:    //四则运算    void Calculate();     //加法运算    void add(T, T);     //减法运算    void subtraction(T, T);     //乘法运算    void multiplication(T, T);    //除法运算    void divide(T, T);     //输出运算符重载    template <class E> friend ostream &operator<<(ostream&, ElementaryArithmetic<E> &);};//四则运算template <class T> void ElementaryArithmetic<T>::Calculate(){    int type;loop1:    system("cls");    cout << endl << "*******************" << endl;    cout << "*   1.加法运算    *" << endl;     cout << "*   2.减法运算    *" << endl;      cout << "*   3.乘法运算    *" << endl;      cout << "*   4.除法运算    *" << endl;     cout << "*******************" << endl << endl;    cout << "请输入菜单项(1-4)：";    try{        cin >> type;        if (type != 1 && type != 2 && type != 3 && type != 4)            throw 1;    }    catch (int e){        cout << endl << "输入错误，请重新输入选项...";        system("pause");        goto loop1;    }        cout << endl << "请输入两个数字：";    cin >> operand1 >> operand2;    if (type == 1){        add(operand1, operand2);        operators = '+';    }    else if (type == 2){        subtraction(operand1, operand2);        operators = '-';    }    else if (type == 3){        multiplication(operand1, operand2);        operators = '*';    }    else if (type == 4){        divide(operand1, operand2);        operators = '/';    }    }//加法运算template <class T> void ElementaryArithmetic<T>::add(T operand1,T operand2){    result = operand1 + operand2;}//减法运算template <class T> void ElementaryArithmetic<T>::subtraction(T operand1, T operand2){    result = operand1 - operand2;}//乘法运算template <class T> void ElementaryArithmetic<T>::multiplication(T operand1, T operand2){    result = operand1 * operand2;}//除法运算template <class T> void ElementaryArithmetic<T>::divide(T operand1, T operand2){    try{        //除数为0，出现异常        if ((operand2 - 0) < 1e-8 && (operand2 - 0) > -1e-8)            throw 0;    }    catch (int){        throw ;    }    result = operand1 / operand2;}//输出运算符重载template <class E> ostream& operator<<(ostream &os, ElementaryArithmetic<E> &result){    os << endl << "计算结果 ： " << result.operand1 << result.operators << result.operand2 << '=' << result.result << endl;    return os;}//三角函数class Trigonometric{private:    double radian;    string type;    double result;public:    //三角函数计算    void Calculate();    //输出运算符重载    friend ostream &operator<<(ostream&, Trigonometric &);};//三角函数计算void Trigonometric::Calculate(){    int option;loop2:    system("cls");    cout << "*******************" << endl;    cout << "*    1.求正弦      *"<< endl;     cout << "*    2.求余弦      *"<< endl;    cout << "*    3.求正切      *"<< endl;    cout << "*******************" << endl << endl;    cout << "请输入菜单项(1-3)：";    try{        cin >> option;        if (option != 1 && option != 2 && option != 3 && option != 4)            throw 2;    }    catch (int e){        cout << endl << "输入错误，请重新输入选项..." ;        system("pause");        goto loop2;    }        cout << endl << "请输入弧度：";    cin >> radian;    if (option == 1){        result = sin(radian);        type = "sin";    }    else if (option == 2){        result = cos(radian);        type = "cos";    }    else if (option == 3){        result = tan(radian);        type = "tan";    }}//输出运算符重载ostream &operator<<(ostream &os, Trigonometric &result){    os << endl << "计算结果 ： " << result.type << "(" << result.radian << ") = " << result.result << endl;    return os;}int main(){    int type;loop:    while (true){        system("cls");        cout << "*******主菜单**********" << endl;        cout << "*                     *" << endl;        cout << "*   1. 四则运算       *" << endl;        cout << "*   2. 三角函数       *" << endl;        cout << "*   3. 退出程序       *" << endl;        cout << "*                     *" << endl;        cout << "***********************" << endl << endl;        cout << "请输入菜单项(1-3)：";        try{            cin >> type;            if (type != 1 && type != 2 && type != 3)                throw - 1;                    if (type == 1){                ElementaryArithmetic<double> calc;                calc.Calculate();                cout << calc;            }            else if (type == 2){                Trigonometric calc;                calc.Calculate();                cout << calc;            }            else if (type == 3)                break;        }        catch (int e){            if (e == -1){                cout << endl << "输入错误，请重新输入选项...";                system("pause");                goto loop;            }            else if (e == 0)                cout << "除数不能为 0 " << endl;                    }        cout << endl;        system("pause");    }    return 0;}

好吧，其实我也不知道为什么要求用模板和运算符重载，感觉没什么必要，典型的作业代码，不过也可能是我思想的局限性。总之，就这样吧。

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