Thread: Reading an Unknown Number of Inputs

I am new to C++, and I have been reading "C++ Primer, 4th Edition" to help me learn. I do the examples in the book to help me practice. This part of the chapter is covering control structures, but I can't get one of the examples to work for me.

The code is suppose to take any values you input (regardless of quantity) and generate their collective sum. I wrote it correctly, it complied just fine.

I input integers but it doesn't give me the sum, and the program will not stop normally unless I ex out the window or I input something that is a non integer.

Code:

#include <iostream>    
int main()    
{        
     int sum = 0, value;      
     // read till end-of-file, calculating a running total of all values read       
     while (std::cin >> value)           
          sum += value; // equivalent to sum = sum + value        
     std::cout << "Sum is: " << sum << std::endl;        
     return 0;     
}

Someone did post on programmersheaven.com forum about this same exact code a few years back, however it didn't help me much or maybe it isn't relevant anymore (some nonsense about ctrl+z, idk).

It would be great if I can get a response soon. I am using Microsoft Visual C++ 2010 IDE.

Originally Posted by Aeias

(some nonsense about ctrl+z, idk).
.

Not nonsense at all, it is called the End of File character. It is different for me though (Ctrl+D).

I did not test it, but the loop should also stop if you enter something other than a number...say a character.

Originally Posted by Aeias

Yes, but for me all ctrl+z dose is undo.

Maybe it is because I am using MS Visual C++ 2010.

:doh:
Press it when running the binary, not when editing the code.

I have done that also.

What do you mean by, running the binary?

(sorry Iam very new)

Originally Posted by Aeias

I have done that also.

What do you mean by, running the binary?

(sorry Iam very new)

When you run the program ..and are supposed to enter a number, either enter something not a number, or possibly press Ctrl Z.
That should stop the loop and print out the sum of the numbers you've already entered.

Originally Posted by manasij7479

When you run the program ..and are supposed to enter a number, either enter something not a number, or possibly press Ctrl Z.
That should stop the loop and print out the sum of the numbers you've already entered.

I have done that, however all that appears in the command window is "^z", and if I press enter the program ends. And if I am not selected on the command prompt window, I hear a loud beep noise. I don't understand exactly how I am suppose to press ctrl+z.

ok, I was using

char response;
std::cin >> response;

before the return.
However I am getting the same result, I type in some integers, I hit ctrl+z I see ^z in the command prompt. Nothing appears, so i hit enter and the console command window closes.

It works fine for me.

[manasij7479@manasijd ~]$ ./a.out
3
4
3
Sum is: 10
[manasij7479@manasijd ~]$

Try entering a letter instead of ^Z and report what happens.

I have tried several letters just a few like A,F,C,T

the only one that did something a little different was ctrl+c which just closed the program sooner.

What compiler or IDE do you use?

Ctrl+C should close the program on spot.
But I am puzzled that the eof character or anything other a number does not end the loop and print the sum.
Do exactly what I'm writing:
Run the program
Enter 5 . Press Enter
Enter a . Press Enter

What happens after that ?

(I'm on a different OS, so stuff regarding eof will be different.)