编程求解分数序列S=1-1/3+1/5-1/7+1/9-…前20项之和。

源代码

#include <stdio.h>

int main()

{
int num = 1, s = 1, t= 1;

double sum = 1.00;

while (num <= 20)

{
s = -s;

t = t + 2;

sum += ( (double) s / t);

num++;

}

printf("前20项和=%0.3f", sum);

}

运行结果图

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