用c语言用while语句计算圆周率的近似值。（直到累加项的绝对值小于 0.00001 ） 公式 : pi /4 ≈1-1/3+1/5-1/7 .......

Sure, I'd love to help you with that! Here's the C code using while loop to approximate the value of pi:

#include<stdio.h>

int main()
{
    double pi = 0.0;
    double frac = 1.0;
    int sign = 1;
    double term = 1.0;
    while(term > 0.00001 || term < -0.00001)
    {
        pi += term;
        sign *= -1;
        frac += 2.0;
        term = sign / frac;
    }
    pi *= 4;
    printf("The approximated value of pi: %f\n", pi);
    return 0;
}

Hope this helps!