例2.4 求1-1/2+1/3-1/4+···+1/99-1/100

#include<stdio.h>

int main()

{

 int sign = 1;

 double deno = 2.0, sum = 1.0, term;//deno分母，sum多项式，term分式

 while (deno <= 100)

 {

  sign = -sign;

  term = sign / deno;

  sum = sum + term;

  deno = deno + 1;

 }

 for(int deno=1;deno<=100;deno++){

  sign = -sign;

  term = sign / deno;

  sum += term;  

 }

 printf("%f\n",sum);

 return 0;

}