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The code:

```
int num=999999; //or generally a very big number (like 10^6, etc.)
int sum=0;
for(int i=num; i>=1; i--) sum+=i;
```

**So basically I want to find the sum of the** `num + num-1 + num-2 +...+ 1`

, **is there any way to make for loop faster or to get rid of it entirely?**

### >Solution :

This seems to be a math problem.

The loop can be avoided by using a formula for the sum of the integers from 1 up to and including a positive integer n, given as

sum = n * (n + 1) / 2