How can I input decimals into my calculator?

[pregunton1]

I'm trying to write a calculator where the numbers are entered from right to left. In order to accomplish this task, I've put together the following code by searching through this forum and grabbing some ideas from other users. Now it works fine but only with integers. So if I want to enter 2.5 and multiply it by 2, it would simply not work. Can somebody give me an idea of how I can modify my program for this to work? I would greatly appreciate it!

#include <iostream>
#include <iomanip>
#include <windows.h>
#include <cstdlib>
#include <stdio.h>
#include <conio.h>
#include <string>
#include <sstream>

using namespace std;

struct console_t
  {
  DWORD  mode;
  HANDLE hstdin;
  HANDLE hstdout;

  console_t()
    {
    hstdin  = GetStdHandle( STD_INPUT_HANDLE  );
    hstdout = GetStdHandle( STD_OUTPUT_HANDLE );
    GetConsoleMode( hstdin, &mode );
    }

  ~console_t()
    {
    if (hstdin != INVALID_HANDLE_VALUE)
      SetConsoleMode( hstdin, mode );
    }

  bool iskeypressed( unsigned timeout_ms = 0 ) const
    {
    return WaitForSingleObject( hstdin, timeout_ms ) == WAIT_OBJECT_0;
    }

  int getkeypress() const
    {
    INPUT_RECORD inrec;
    DWORD        count;

    if (hstdin == INVALID_HANDLE_VALUE) return -1;
    SetConsoleMode( hstdin, 0 );

    do ReadConsoleInput( hstdin, &inrec, 1, &count );
    while ((inrec.EventType != KEY_EVENT) || inrec.Event.KeyEvent.bKeyDown);

    SetConsoleMode( hstdin, mode );

    return inrec.Event.KeyEvent.wVirtualKeyCode;
    }

  void gotoxy( int column, int line )
    {
    COORD coord;
    coord.X = column;
    coord.Y = line;
    SetConsoleCursorPosition( hstdout, coord );
    }

  void clearscreen()
    {
    CONSOLE_SCREEN_BUFFER_INFO csbi;
    DWORD                      count;
    DWORD                      cellCount;
    COORD                      homeCoords = { 0, 0 };

    if (hstdout == INVALID_HANDLE_VALUE) return;

    if (!GetConsoleScreenBufferInfo( hstdout, &csbi )) return;
    cellCount = csbi.dwSize.X * csbi.dwSize.Y;

    if (!FillConsoleOutputCharacter(
      hstdout,
      (TCHAR) ' ',
      cellCount,
      homeCoords,
      &count
      )) return;

    if (!FillConsoleOutputAttribute(
      hstdout,
      csbi.wAttributes,
      cellCount,
      homeCoords,
      &count
      )) return;

    SetConsoleCursorPosition( hstdout, homeCoords );
    }
  };

int a,c,n,m;
char b,d;
inline int addizione(int a, int c){      //Function +
      return m=a+c;
      }
     inline int sottrazione(int a, int c){  //Function -
            return m=a-c;
            }
           inline int divisione(int a, int c){    //Function /
                  return m=a/c;
                  }
                 inline int moltiplicazione(int a, int c){    //Function *
                        return m=a*c;
                        }

int main()
{
   PROBANDO:
   console_t console;
   string pass ="";
   char ch;
   ch = _getch();
   while(ch != 13){
      pass.push_back(ch);
      int zerokey = 0;
      zerokey = console.getkeypress();
      if(zerokey == '0' || zerokey == '1' || zerokey == '2' || zerokey == '3' || zerokey == '4' || zerokey == '5' || zerokey == '6' || zerokey == '7' || zerokey == '8' || zerokey == '9')
      {
            switch(zerokey){
            case '0': zerokey = 0; break;
            case '1': zerokey = 1; break;
            case '2': zerokey = 2; break;
            case '3': zerokey = 3; break;
            case '4': zerokey = 4; break;
            case '5': zerokey = 5; break;
            case '6': zerokey = 6; break;
            case '7': zerokey = 7; break;
            case '8': zerokey = 8; break;
            case '9': zerokey = 9; break;
            return zerokey;
        }

        console.clearscreen();
        stringstream ss(pass);
        int thisVar;
        if( (ss >> thisVar).fail() ) {       //here you do the conversion to integer whole number...
        //error
        }
        a = thisVar;    //here you store the value into the variable a...
        cout << setw(11) << a;

        ch = _getch();
      }
      else if(zerokey == 189) { //This will subtract the numbers...
          zerokey = '-';
          b = zerokey;
          goto LOOP2;
      }

      else if(zerokey == 187) {
          zerokey = '+';
          b = zerokey;
          goto LOOP2;
      }

      else if(zerokey == 191) {
          zerokey = '/';
          b = zerokey;
          goto LOOP2;
      }

      else if(zerokey == 219) {
          zerokey = '*';
          b = zerokey;
          goto LOOP2;
      }

      else if(zerokey == 8) {
          console.clearscreen();
          goto PROBANDO;
      }

   } //closes the while statement...

          LOOP:
            int thiskey;
            thiskey = console.getkeypress();
            if(thiskey == 189) { //This will subtract the numbers...
                thiskey = 0;
                thiskey = '-';
                b = thiskey;
                goto LOOP2;
            }

            else if(thiskey == 187) {
                thiskey = 0;
                thiskey = '+';
                b = thiskey;
                goto LOOP2;
            }

            else if(thiskey == 191) {
                thiskey = 0;
                thiskey = '/';
                b = thiskey;
                goto LOOP2;
            }

            else if(thiskey == 219) {
                thiskey = 0;
                thiskey = '*';
                b = thiskey;
                goto LOOP2;
            }

            else if(thiskey == 8) {
                console.clearscreen();
                goto PROBANDO;
            }

          LOOP2:

   string pass2 ="";
   char ch2;
   ch2 = _getch();
   while(ch2 != 13){//character 13 is enter
      pass2.push_back(ch2);
      int onekey = 0;
      onekey = console.getkeypress();
      if(onekey == '0' || onekey == '1' || onekey == '2' || onekey == '3' || onekey == '4' || onekey == '5' || onekey == '6' || onekey == '7' || onekey == '8' || onekey == '9')
      {
            switch(onekey){
            case '0': onekey = 0; break;
            case '1': onekey = 1; break;
            case '2': onekey = 2; break;
            case '3': onekey = 3; break;
            case '4': onekey = 4; break;
            case '5': onekey = 5; break;
            case '6': onekey = 6; break;
            case '7': onekey = 7; break;
            case '8': onekey = 8; break;
            case '9': onekey = 9; break;
            return onekey;
        }

        console.clearscreen();
        stringstream ss(pass2);
        int thisVar2;
        if( (ss >> thisVar2).fail() ) {       //here you do the conversion to integer whole number...
        //error
        }
        c = thisVar2;    //here you store the value into the variable a...
        cout << setw(11) << c;

        ch2 = _getch();
      }

      else if(onekey == 13) {
        goto FINAL;
      }

      else if(onekey == 189) { //In case we want to subtract again then we repeat the process...
          onekey = '-';
          b = onekey;
          goto LOOP2;
      }

      else if(onekey == 187) {
          onekey = '+';
          b = onekey;
          goto LOOP2;
      }

      else if(onekey == 191) {
          onekey = '/';
          b = onekey;
          goto LOOP2;
      }

      else if(onekey == 219) {
          onekey = '*';
          b = onekey;
          goto LOOP2;
      }

      else if(onekey == 8) {
          console.clearscreen();
          goto PROBANDO;
      }
   } //closes the while statement...

          FINAL:
          console.clearscreen();
          if(b=='+'){
                    n = addizione(a,c);
                    cout << setw(11) << n;
                    a=n;
                    }else if(b=='-'){
                          n=sottrazione(a,c);
                          cout << setw(11) << n;
                          a=n;
                          }else if(b=='/'){
                                n=divisione(a,c);
                                cout << setw(11) << n;
                                a=n;
                                }else if(b=='*'){
                                      n=moltiplicazione(a,c);
                                      cout << setw(11) << n;
                                      a=n;
                                      }
                                      goto LOOP;   /*goes to loop and allows to
                                                   automatically continue operating*/
          system("pause");
          return 0;
          }

[buffbill]

The four functions (+,-,*,/) are all written for int types and this is the type you convert your char digits to also. As you are aware int types cannot store fractions. It seems that instead of converting char types to int you will have to convert to double or float type with a function like atof() or write your own.
Hope this helps.