 scosant
12/17/2012 - 11:21 AM

## projecteuler006 - sum square difference

projecteuler006 - sum square difference

``````/* Scott Santarromana, 2010
* projecteuler006 - sum square difference
*
* The sum of the squares of the first ten natural numbers is,
* 1^2 + 2^2 + ... + 10^2 = 385
* The square of the sum of the first ten natural numbers is,
* (1 + 2 + ... + 10)^2 = 55^2 = 3025
* Hence the difference between the sum of the squares of the
* first ten natural numbers and the square of the sum
* is 3025 - 385 = 2640.
* Find the difference between the sum of the squares of
* the first one hundred natural numbers and the square of
* the sum.
*/

#include <iostream>

int64_t CalculateSquareOfSum(int64_t num);
int64_t CalculateSumOfSquares(int64_t num);

int main(int argc, char *argv[])
{
int num = 100;
int result = CalculateSumOfSquares(num) - CalculateSquareOfSum(num);
std::cout << "Difference between sum of squares and square of sum"
<< std::endl << "of first " << num << " numbers is "
<< result << std::endl;
return 0;
}

int64_t CalculateSquareOfSum(int64_t num) {
int64_t result = 0;
for (int64_t i = 1; i <= num; i++) {
result += i;
}
return result * result;
}

int64_t CalculateSumOfSquares(int64_t num) {
int64_t result = 0;
for (int64_t i = 1; i <= num; i++) {
result += i * i;
}
return result;
}
``````