finish the loop program

Question

// Finish the following program which adds up all integers from 0 to
// the user's given number inclusively using a FOR loop. The total should be
// assigned to the variable 'total'.

#include <iostream>
using namespace std;

int main()
{
int number;
int total;

cout << "Enter a positive integer to find the summation of"
<< " all numbers from 0 to the given number." << endl;
cin >> number;

// TODO - Add your code here

cout << "Total : " << total << endl;

return 0;
}

Answer 1

for (int i=0;i<=number; i++)
{
total=total+i; //total =0
}
cout <<total;

Answer 2

while(number!=0)
{total+=number--;}

Answer 3

I agree @Neetish, instead of using a for loop like was asked, lets be rebellious and not use it :) ( btw total is not initialized )

Here's my share:
total = number / 2.0 * ( number + 1 );

Answer 4

hmm, 😅 from now on I ll be forever rebellious, @dennis and loved the direct formula way