c語言前項和

❶ 怎樣用C語言求1-1/3+1/5-1/7........前15項和

#include "stdio.h"
#include "math.h"
int main()
{
float sum = 0;
float k = -1;
for (int i=0;i<15;i++)
{
sum+=1.0/(2*i+1)*pow(k,i);
}
printf("%f\n",sum);
return 0;
}