# Cant figure out how to do this!

This is a discussion on Cant figure out how to do this! within the C++ Programming forums, part of the General Programming Boards category; Im not too good at C++, plus, I am not good at anything. Anyways, I am trying to make a ...

1. ## Cant figure out how to do this!

Im not too good at C++, plus, I am not good at anything. Anyways, I am trying to make a prog that takes a number from the user and then adds all the numbers that lead up to it together. For example

cin>>5 (num)

This is the part I dont know how to do. I know i have to use a loop, and I know how to make it count up to the number, but how do i get it to take the number it gets and put it in some kind of queue that will be added up later (0+1+2+3+4+5)?

cout<<15 (sum)

any help would be great.

2. If all you're doing is adding all of the numbers before the number entered then you can easily do this with a simple loop.
Code:
```int total;
for ( int i = 0; i < num; i++ ) {
total += i;
}
cout << total;```

3. Code:
```#include<iostream.h>
int main()
{

int num;
int sum = 0;

cout << "Enter a number: ";
cin >> num;
while(num > 0)
{
sum += num;
--num;
}
cout << "Sum is: " << sum << endl;

return 0;
}```
This can be made into a function. Here is one solution.

4. ok, i understand now, i didnt know about that += what is that?

5. total += i

is the same as

total = total + i

It's just one of those short-hand things that makes life easier. You can use that "trick" for any normal operator, like:

total -= i; (total = total - i; )
total *=i; (total = total * i; )
total /=i; (total = total / i; )

6. ahh, i see