c++ sum up numbers
// Method 1: Mathematical -> Sum up numbers from 1 to n
int sum(int n){
return (n * (n+1)) / 2;
}
// Method 2: Using a for-loop -> Sum up numbers from 1 to n
int sum(int n){
int tempSum = 0;
for (int i = n; i > 0; i--){
tempSum += i;
}
return tempSum;
}
// Method 3: Using recursion -> Sum up numbers from 1 to n
int sum(int n){
return n > 0 ? n + sum(n-1) : 0;
}