BOOKC, this time share about calculator program in c++ using functions
Write a program for a simple c++ calculator which have different functions for different operations. Make a menu base selection screen using switch statement. Ever operation should have its own function. This code may also be use as a mini project to start.
Calculator should have following operations.
• Subtraction
• Multiplication
•  Division
• Square root
• Factorial
• Exponential

This code has been tested on Code blocks c++ compiler

C++ Source Code:

`#include<iostream>#include<conio.h>#include<math.h>#include<stdlib.h>#include<iomanip>  char op;using namespace std;void sum()   {         int sum = 0;    int n;    int numberitems;    cout << "Enter number of items: \n";    cin >> numberitems;    for(int i=0;i<numberitems;i++)    {        cout<< "Enter number "<<i<<":\n\n" ;        cin>>n;         sum+=n;    }    cout<<"sum is: "<< sum<<endl<<endl;        }void diff()    {     int diff;     int n1,n2;     cout<<"enter two numbers to find their difference:\n\n";     cout<<"enter first number:";     cin>>n1;     cout<<"\nenter second number:";     cin>>n2;     diff=n1-n2;     cout<<"\ndifference is:"<<diff<<endl<<endl;     }     void pro()        {     int pro=1;     int n;     int numberitems;     cout<<"enter number of items:\n";     cin>>numberitems;     for(int i=0;i<=numberitems;i++)     {             cout<<"\nenter item "<<i<<":";             cin>>n;             pro*=n;     }                  cout<<"product is:"<<pro<<endl<<endl;         }        void div()     {      int div;      int n1;      int n2;      cout<<"enter 2 numbers to find their quotient\n\n";      cout<<"enter numerator:";      cin>>n1;      cout<<"\nenter denominator:";      cin>>n2;      div=n1/n2;      cout<<"\nquotient is:"<<div<<endl<<endl;      }      void power()     {          long int p;     int res=1,n;      cout<<"enter number:";     cin>>n;     cout<<"\nenter power:";     cin>>p;     for(int i=1;i<=p;i++)     {      res=n*res;     }      cout<<n<<"\n power "<<p<<" is :"<<res<<endl;     }        void sq()     {     float s;     int n;     cout<<"enter number to find its square root:";     cin>>n;     s=sqrt(n);     cout<<"\nsquare root of "<<n<<" is :"<<s<<endl;     } void fact()     {      long int f=1;      int c=1,n;      cout<<"enter number to find its factorial:";      cin>>n;      while(c<=n)      {                 f=f*c;                 c+=1;      }                      cout<<"\nfactorial of "<<n<<" is :"<<f<<endl;           }void expo()     {          long double res=1,p;      double e=2.718281828;          cout<<"enter power of exponential function:";     cin>>p;     for(int i=1;i<=p;i++)     {      res=e*res;     }      cout<<" e^ "<<p<<" is :"<<res<<endl;                      }int main(){               system("cls");    do    {                    system("pause");                  system("cls");        cout<<"***which operation you want to perform***\n";    cout<<"press 0 for exit\n";    cout<<"press 1 for addition \n";    cout<<"press 2 for subtraction\n";    cout<<"press 3 for multiplication\n";    cout<<"press 4 for division\n";    cout<<"press 5 for power calculation\n";    cout<<"press 6 for square root \n";    cout<<"press 7 for factorial calculation\n";    cout<<"press 8 for exponential calculation\n";    cout<<"press option:";    cin>>op;    switch(op)    {              case '1':              sum();                            break;              case '2':              diff();              break;              case '3':              pro();              break;              case '4':              div();              break;              case '5':              power();              break;              case '6':              sq();              break;              case '7':              fact();              break;              case '8':              expo();              break;                   case '0':              exit(0);                  default:              cout<<"invalid input"  ;              system("cls");    }     }                                                                             while(op!='0');                                        getch();                    }`

Program output video

Image output
 output on code blocks console

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