how i use function in c programing sum of the series

[Faisal440]

1+2+...+n

[zapshe]

Depends on the series. If it's just adding 1 until you reach n then:

int a = 0;
for (int i = 0; i <= n; i++)
	a += i;

EDIT: (wrong equation!)

[keskiverto]

Faisal440 wrote:

1+2+...+n

is an arithmetic series. The sum of arithmetic series has an analytic solution. A simple equation.