c语言求π的近似值的另一种方法为何不行

Question

//计算π的近似值
#include
#include

void main()
{
int count=1,j;
double pi=0,n=1.0;
while(fabs(n)>1e-6)
{
count++;
j=(2*count-1);
if(count%2==0)
{
j=-j;
}
n=1.0/j;
pi=1+n;
}
pi*=4;
printf("%f",n);
printf("π的近似值为%lf\n",pi);

}

运行结果
0.000001
π的近似值为4.000004

参考代码
#include
#include
int main()
{

int sign = 1;

double pi = 0.0,
n = 1.0,
term = 1.0;//term表示当前项

while (fabs(term) >= 1e-6)

{

pi += term;

n += 2;

sign = -sign;

term = sign / n;

}

pi *= 4;

printf("pi=%10.8f\n", pi);

return 0;
}

运行结果
pi=3.14159065
Press any key to continue

Answer 1

问题解决的话，请点下采纳

#include <stdio.h>
#include <math.h>

int main()
{
    int count=1,j;
    double pi=1,n=1.0;
    while(fabs(n)>1e-6)
    {
        count++;
        j=(2*count-1);
        if(count%2==0)
        {
            j=-j;
        }
        n=1.0/j;
        pi=pi+n;
    }
    pi*=4;
    printf("%f",n);
    printf("π的近似值为%lf\n",pi);
}