小型项目：基于菜单的计算机系统

/*
calc.cpp实现了计算机系统。开始时，他显示一个菜单，以选择计算器的类型。如果用户选择了
标准型计算器，则出现标准型计算器的菜单，而如果用户选择了科学性计算器，则出现科学计算器
的菜单，最后一个的选项是退出程序。
在标准计算器中，选项有加、减、乘、除等，而在科学计算器中，选项有求幂、阶乘、开方等。
在本程序中，定义了新旧计算器的宏开关，新计算器接受输入值，而旧计算器的操作数则是前次操
作的结果。
本项目没有考虑异常处理，所以输入输出时不要输入非数字字符串。
数据范围还不够大，将在往后进一步改进。
*/
//包含预处理宏和头文件的文件
#include<iostream>
using namespace std;
#include<conio.h>
#include<math.h>
#include<stdlib.h>
#include<stdio.h>
#define new_cal 1
#define old_cal 0
//stand_calc 类定义了标准计算器的函数
class stand_calc
{
    /*标准计算器函数的原型。这些函数都是静态的，所以调用他们时，
    只使用类名即可，没有必要创建该类的实例。*/
public:
    static double addition(double,double);
    static double substract(double,double);
    static double multiplication(double,double);
    static double division(double,double*);
    static double modulus(double*,double*);
};
//science_calc类定义了科学型计算器的函数
class science_calc
{
public:
    static double square(double);
    static double cube(double);
    static double power(double,double);
    static double sq_root(double);
    static long int fact(double);
    static double sin_func(double);
    static double cos_func(double);
    static double tan_func(double);
};
double stand_calc::addition(double a, double b)
{
    return (a+b);
}
double stand_calc::substract(double a, double b)
{
    return (a-b);
}
double stand_calc::multiplication(double a, double b)
{
    return (a*b);
}
/*除法函数将执行被除数和除数的相除，该函数有两个参数，其中一个是变量副本，
另一个是指针。之所以如此，是因为如果除数是0，则该函数将显示再次输入除数的
信息。使用指针后，再次输入的除数值也会在主函数中被更新。*/
double stand_calc::division(double a, double*b)
{
    while(*b==0)
    {
        cout<<"
Cannot divide by zero"<<endl;
        cout<<"
Enter the second number again:";
        cin>>*b;
    }
    return (a/(*b));
}
/*求余函数将执行被除数和除数的相除，并返回除法的余数。和除法操作类似，它的
除数也不能为0。由于不能对双精度数求余，所以得先转换成整数。*/
double stand_calc::modulus(double* a, double*b)
{
    while(*b==0)
    {
        cout<<"
Cannot divide by zero"<<endl;
        cout<<"
Enter the second number again:";
        cin>>*b;
    }
    int x=(int)*a;
    int y=(int)*b;
    if(*a-x>0||*b-y>0)
    {
        cout<<"
Converting decimal number into an integer to perform modulus";
    }
    *a=x;
    *b=y;
    return ((x)%(y));
}

//science_calcl类的函数声明由此开始
double science_calc::square(double x)
{
    return (pow(x,2));
}
double science_calc::cube(double x)
{
    return (pow(x,3));
}
double science_calc::power(double x,double y)
{
    return (pow(x,y));
}
double science_calc::sq_root(double x)
{
    return (sqrt(x));
}
long int science_calc::fact(double x)
{
    int n=(int)x;
    long int f=1;
    while(n>1)
    {
        f*=n;
        n--;
    }
    return f;
}
double science_calc::sin_func(double x)
{
    return (sin(x));
}
double science_calc::cos_func(double x)
{
    return (cos(x));
}
double science_calc::tan_func(double x)
{
    return (tan(x));
}

int main()
{
    double num1,num2,num3,temp;
    int choice1=0,choice2,flag;
    //主菜单的循环，程序从此开始，他将显示选择计算器类型的菜单
    do
    {
//   clrsrc();//清除屏幕
        system("cls");
        cout<<"===============Type of Calculators===============";
        cout<<"
1	Standard Calculator
2	Scientific Calculator
3	Quit"<<endl;
        cin>>choice1;
        flag=new_cal;
        //根据主菜单中的输入选项，执行相应操作
        switch(choice1)
        {
        case 1:
            do
            {
                //  clrscr();
                system("cls");
                  cout<<"================Standard Calculator================";
                  cout<<"
1	Addition
2	Substraction
3	Multification
4	Division
5	Modulus
6	Return to Previous Menu
7	Quit";
                  //只有在旧计算器模式时，选项8才会显示，此时一个操作数已经存储在计算机的内存中
                if(flag==old_cal)
                {
                    cout<<"
8	Clear Memory";
                }
                cout<<"
Choose the type of calculator:"<<endl;
                cin>>choice2;
                switch(choice2)
                {
                case 1:
                  // 如果是新计算机模式，则接受第一个操作数，否则第一个操作数由上一次计算结果提供
                  if(flag==new_cal)
                  {
                      cout<<"Enter first number:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
First num is"<<num1<<endl;
                  }
                  cout<<"Enter second number:";
                  cin>>num2;
                  num3=stand_calc::addition(num1,num2);
                  cout<<"
Addition of"<<num1<<" and"<<num2<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                case 2:
                  // 如果是新计算机模式，则接受第一个操作数，否则第一个操作数由上一次计算结果提供
                  if(flag==new_cal)
                  {
                      cout<<"Enter first number:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
First num is"<<num1<<endl;
                  }
                  cout<<"Enter second number:";
                  cin>>num2;
                  num3=stand_calc::substract(num1,num2);
                  cout<<"
Substraction of"<<num1<<" from"<<num2<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                   case 3:
                  // 如果是新计算机模式，则接受第一个操作数，否则第一个操作数由上一次计算结果提供
                  if(flag==new_cal)
                  {
                      cout<<"Enter first number:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
First num is"<<num1<<endl;
                  }
                  cout<<"Enter second number:";
                  cin>>num2;
                  num3=stand_calc::multiplication(num1,num2);
                  cout<<"
Multification of"<<num1<<" and"<<num2<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                   case 4:
                  // 如果是新计算机模式，则接受第一个操作数，否则第一个操作数由上一次计算结果提供
                  if(flag==new_cal)
                  {
                      cout<<"Enter first number:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
First num is"<<num1<<endl;
                  }
                  cout<<"Enter second number:";
                  cin>>num2;
                  num3=stand_calc::division(num1,&num2);
                  cout<<"
Division of"<<num1<<" by"<<num2<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                   case 5:
                  // 如果是新计算机模式，则接受第一个操作数，否则第一个操作数由上一次计算结果提供
                  if(flag==new_cal)
                  {
                      cout<<"Enter first number:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
First num is"<<num1<<endl;
                  }
                  cout<<"Enter second number:";
                  cin>>num2;
                  num3=stand_calc::modulus(&num1,&num2);
                  cout<<"
Modulus of"<<num1<<" by"<<num2<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                   case 6:
                       cout<<"
Returning to previous menu.";
                       cout<<"
press any key to continue......";
                       getch();
                       break;
                   case 7:
                    cout<<"
Quitting......";
                    cout<<"
press any key to continue......";
                    getch();
                    exit(0);
                   case 8:
                    //如果是新计算机模式，则8是非法选项，否则8选项用以重启一个新的计算
                    if(flag==new_cal)
                    {
                        cout<<"
Invalid choice.";
                        cout<<"
press any key to continue......";
                        getch();
                    }
                    else
                    {
                        temp=0;
                        flag=new_cal;
                    }
                    break;
                   default:
                    cout<<"
Invalid choice.";
                    cout<<"
press any key to continue......";
                    getch();
                    break;
                 }
                }while(choice2!=6);
                break;
                case 2:
               do
               {
            //      clrscr();
                 system("cls");
                  cout<<"================Scientific Calculator================";
                  cout<<"
1	Square
2	Cube
3	Power
4	Factorial
5	Sin
6	Cos
7	Tan
8	Return to previous menu
9	Quit";
                  //只有在旧计算器模式时，选项8才会显示，此时一个操作数已经存储在计算机的内存中
                if(flag==old_cal)
                {
                    cout<<"
10	Clear Memory";
                }
                cout<<"
Choose the type of calculator:"<<endl;
                cin>>choice2;
                switch(choice2)
                {
                case 1:
                  if(flag==new_cal)
                  {
                      cout<<"Enter number to find square:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
Number is"<<num1<<endl;
                  }
                  num3=science_calc::square(num1);
                  cout<<"
Square of"<<num1<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                case 2:
                  if(flag==new_cal)
                  {
                      cout<<"Enter number to find cube:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
Number is"<<num1<<endl;
                  }
                  num3=science_calc::cube(num1);
                  cout<<"
Cube of"<<num1<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
            case 3:
                if(flag==new_cal)
                  {
                      cout<<"Enter first number for base to find power:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
First number is"<<num1<<endl;
                  }
                  cout<<"Enter second number for base to fine power:";
                  cin>>num2;
                  num3=science_calc::power(num1,num2);
                  cout<<"
Power of"<<num1<<"to the power "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                   case 4:
                  if(flag==new_cal)
                  {
                      cout<<"Enter number to find factorial:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
Number to find factorial is"<<num1<<endl;
                  }
                  num3=science_calc::fact(num1);
                  cout<<"
Factorial of"<<num1<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                   case 5:
                  if(flag==new_cal)
                  {
                      cout<<"Enter number to find sin value:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
Number for sin value is"<<num1<<endl;
                  }
                  num3=science_calc::sin_func(num1);
                  cout<<"
Sin value of"<<num1<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                   case 6:
                    if(flag==new_cal)
                  {
                      cout<<"Enter number to find cos value:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
Number for cos value is"<<num1<<endl;
                  }
                  num3=science_calc::cos_func(num1);
                  cout<<"
Cos value of"<<num1<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                   case 7:
                    if(flag==new_cal)
                  {
                      cout<<"Enter number to find tan value:";
                      cin>>num1;
                  }
                  else
                  {
                      num1=temp;
                      cout<<"
Number for tan value is"<<num1<<endl;
                  }
                  num3=science_calc::tan_func(num1);
                  cout<<"
Tan value of"<<num1<<" is "<<num3;
                  cout<<"
Press any key to continue......"<<endl;
                  getch();
                  temp=num3;
                  flag=old_cal;
                  break;
                   case 8:
                       cout<<"
Returning to previous menu.";
                       cout<<"
press any key to continue......";
                       getch();
                       break;
                   case 9:
                    cout<<"
Quitting......";
                    cout<<"
press any key to continue......";
                    getch();
                    exit(0);
                   case 10:
                    if(flag==new_cal)
                    {
                        cout<<"
Invalid choice.";
                        cout<<"
press any key to continue......";
                        getch();
                    }
                    else
                    {
                        temp=0;
                        flag=new_cal;
                    }
                    break;
                   default:
                    cout<<"
Invalid choice.";
                    cout<<"
press any key to continue......";
                    getch();
                    break;
                }
            }while(choice2!=8);
            break;
              case 3:
                cout<<"
Quitting......";
                cout<<"
press any key to continue......";
                getch();
                break;
        default:
            cout<<"
Invalid choice.";
            cout<<"
press any key to continue......";
            getch();
            break;
        }
    }while(choice1!=3);

    return 0;
}

执行效果图如下（可以自己尝试）：

除了system("cls")清除屏幕的应用，我觉得突出的一点就是新旧计算模式。

该程序主要是函数的书写以及循环与条件的层层嵌入。

版权声明：本文为博主原创文章，未经博主允许不得转载。