CashRegister problem

I am making a cash register program that sks you for the amount and quantity of the item. I also want to put a Subtotal in the bottom of the window. But when I enter a second item... The subtotal resets. I want it to keep adding to the subtotal until no more items are left. How can I achieve this?

[note:] This is a Console App

I didn't see your code so I can't say exactly what is wrong.

But since you want to preserve a value and add to it in cycles, it seems to me you are missing there a static variable. Just for fun, change the definition of the variable you have for storing the subtotal to:

Code:

static <type> variable_name

Hmm.... nope.

Heres the code

Code:

#include <iostream.h>
#include <stdlib.h>
#include <conio.c>
#include <windows.h>
#include <stdio.h>

int count = 0;
int stop = 0;
float prc;
int itmnum = 1;
int qty;

static float sub;

void subttl();
void getprc();
void getqty();
void title();



int main (int argc, char *argv[])
{
   for(int count = 0; count < 20 && stop == 0; count++){
             do{
                system("CLS");
                gotoxy(0,0);
                title();
                subttl();
                gotoxy(10,7);
                getprc();
                subttl();
                gotoxy(10,8);
                getqty();
                itmnum = itmnum + 1;
                }
                while(stop == 0);

             }
   getchar();
   return 0;
}

void title()
{
     textcolor(WHITE);
     cout<<"Cash Register v.2.0b\n"
     <<"_____________________________";

}

void getprc()
{
     cout<<"Enter Price of item number "<<itmnum<<": "; cin>>prc;
                  if(prc == 0){
                  stop = 1;
                  }

}

void getqty()
{
     cout<<"Enter Quantity: "; cin>>qty;
}

void subttl()
{
   gotoxy(20,17);
   sub = prc*qty;
   cout<<"Subtotal: "<<sub;
}

You never increment the product number.

To fix your reseting problem, originally set the subtotal to 0. Also, replace this:

sub = prc*qty;

with this:

sub += prc*qty;

THANK YOU

I didnt even know about +=
ive notice these

*=
-=

what do they mean?

a+=b is the same as a=a+b

Same with the rest.

When you write var = var op value, you can shorthand it to var op= value

thus a = a + 1 is the same as a += 1
or a = a / (12 + b) is the same as a /= (12 + b)

In the last example the parentesis are still necessary, since the compiler will remove your shorthand and otherwise calculate a / 12 + b

Vicious,

The "shorthand" that the other folks have been referring to is really a compiler tool.

Since C++ compiles in a single pass, innovations to the language were implemented to make the process more efficient.

The combined assignment operators are an example of abbreviated operations that allow the compiler to compile our source code in one pass more effectively.

The 'ternary' operator is another good example.

Code:

max = (a > b) ? a : b;

substitutes for:

Code:

if (a > b)
     max = a;
else
     max = b;

(We think we're being cool... like the other 99.999999% of the world knows what the heck we're doing anyway!)