Calculator in C++

Calculator in C++

I am new to C and C++, but I wrote this calculator in C++. It compiles okay on borland 5.5, and can do addition, subtraction, multiplication, and division of two numbers. If you type any characters except numbers, +,-,*,/,or e, there will be lots of beeping noises and error messages!

Please post any ways I can improve this code or my programming in general!
(Additions such as square roots, etc. will be appreciated)
*****Planned changes: Add a constant for pi, add squared and square root, allow calculation of roman numerals.*****

1.  /*

2.    Program: Fett Calculator

3.   

4.    File:C:\borland\bcc55\bin\cpp\calc

5.   

6.    Function: Calculator, very simple

7.   

8.    Author: Mister-Fett

9.   

10.  Revision: Version 1.0, distributed 9/17/04

11.*/

12.#include <iostream.h>

13.#include <conio.h>

14.int mc(int x, int y) //Multiply two numbers

15.{

16.  cout <<"\n\n"<< x <<" times "<< y <<" equals ";

17.  return (x*y);

18.}

19.int ac(int a, int b) //Add two numbers

20.{

21.  cout <<"\n\n"<< a <<" plus "<< b <<" equals ";

22.  return (a+b);

23.}

24.int sc(int z, int c) //Subtract two numbers

25.{

26.  cout <<"\n\n"<< z <<" minus "<< c <<" equals ";

27.  return (z-c);

28.}

29.int dc(int o, int t) //Divide two numbers

30.{

31.  cout <<"\n\n"<< o <<" divided by "<< t <<" equals ";

32.  return (o/t);

33.}

34.void calc(char choice)

35.{

36.  int on,tw,thr;

37.         if (choice == '+') //This whole block checks what the user wants to calculate, and refers to the proper routine to calculate it.

38.  {

39.         cout<<"You selected "<<choice<<". Please enter two numbers,\nsepperated by spaces,";

40.         cout<<"that you want to add."<<endl;//print instructions for the user

41.         cin>>on;//Get the value of variable on

42.         cin>>tw;//Get the value of variable tw

43.         thr=ac(on,tw);//Get the sum of on and tw, and assign that value to thr

44.         cout<<thr<<"\n\n\n\aThanks for using my calculator!";//Print a thank you message

45.  }

46.  else if (choice =='-')

47.  {

48.         cout<<"You selected "<<choice<<". Please enter two numbers,\nsepperated by spaces, that you want to subtract."<<endl;

49.         cin>>on;

50.         cin>>tw;

51.         thr=sc(on,tw);

52.         cout<<thr<<"\n\n\n\aThanks for using my calculator!";

53.  }

54.  else if (choice =='*')

55.  {

56.         cout<<"You selected "<<choice<<". Please enter two numbers,\nsepperated by spaces, that you want to multiply."<<endl;

57.         cin>>on;

58.         cin>>tw;

59.         thr=mc(on,tw);

60.         cout<<thr<<"\n\n\n\aThanks for using my calculator!";

61.  }

62.  else if (choice =='/')

63.  {

64.         cout<<"You selected "<<choice<<". Please enter two numbers,\nsepperated by spaces, that you want to divide."<<endl;

65.         cin>>on;

66.         cin>>tw;

67.         thr=dc(on,tw);

68.         cout<<thr<<"\n\n\n\aThanks for using my calculator";

69.  }

70.  else

71.  {

72.         cout<<"\nPlease reenter that value.\n\a";

73.         cin>>choice;

74.         calc(choice,);

75.  }

76.}

77.void main()

78.{

79.  clrscr();

80.  int one, two, three;

81.  char choice;

82.  while (choice != 'e')

83.  {

84.         cout<<"\nPlease enter +,-,*, or / and then two numbers,\nsepperated by spaces, that you wish to\nadd,subtract,multiply,or divide.\nType e and press enter to exit.";

85.         cin>>choice;

86.         if (choice != 'e')

87.         {

88.                 calc(choice);

89.         }             

90.  }

91.}