c语言：求多项式1-1/2+1/3-1/4+...+1/99-1/100的值，3种循环实现

方法一：for循环实现
程序：
#include<stdio.h>
int main()
{
double i = 0, t = 0,sum = 0,sign = -1;
for (i = 1; i <= 100; i++)
{
sign = -sign;
t =sign/ i;
sum = sum + t;
}
printf("sum=%lf\n",sum);
return 0;
}
方法二：while循环实现
程序：
#include<stdio.h>
int main()
{
double i = 1, t = 0,sum = 0,sign = -1;
while (i <= 100)
{
sign = -sign;
t =sign/ i;
sum = sum + t;
i++;
}
printf("sum=%lf\n",sum);
return 0;
}
方法三：do...while循环实现
#include<stdio.h>
int main()
{
double i = 1, t = 0,sum = 0,sign = -1;
do
{
sign = -sign;
t =sign/ i;
sum = sum + t;
i++;
}
while (i <= 100);
printf("sum=%lf\n",sum);
return 0;
}
结果：
sum=0.688172
请按任意键继续. . .