Sum of numbers

This is a discussion on Sum of numbers within the C++ Programming forums, part of the General Programming Boards category; The purpose of this program is to display the sums of all of the numbers from one to the input ...

1. Sum of numbers

The purpose of this program is to display the sums of all of the numbers from one to the input number. Example if i enter 5 i want it to add the numbers 1+2+3+4+5 = 15 or if i enter 225 it will add 1+2+.....225

Here is what i am working with

insert
Code:
```#include <iostream.h>

void main()
{
int Number, Sum;
Sum = 0;
cout << "Enter a number: " << endl;
cin >> Number;

while (Number >= 0)
{
Sum = Sum + Number;
cout << "Current Total " << Sum << endl;
cout << "Enter a number: " << endl;
cin >> Number;

}

cout << "The total is " << Sum << endl;

}```
It works fine when i go in order 1+2+3+.....10 but it does not add all i need.

Any hints will help thanks in advance.

2. Instead of asking for a new number, you should be subtracting one from the number.

3. Code:
`std::cout << (Number*(Number+1)/2) << std::endl;`

or, if you want to learn programming, consider two loops. I am going to write the outer loop for you, because this is a good habit to get into early while you are learning
Code:
```while(std::cin >> Number && Number > 0) {
int Sum = 0;
for(....)
std::cout << Sum;
}```
This solves a lot of common bugs, first off realize that && is left to right, so the left hand side gets evaluated first, the right hand side is evaluated only when the left is true. The result of a stream input operation, is a stream. This is what lets you do cin >> a >> b; If you evaluate a stream in a boolian context it is true only if all the operations prior to this have been successful. If someone inputs 15, and then a letter your program loops forever, when done this way it exits.

4. Not trying to suggest that you don't sum up those numbers, but the formula:
y = x*(x+1)/2 gives the sum you are calculating.
You can at least use that to check that your answers are correct.