牛顿迭代法求平方根

 1 #include <stdio.h>
 2 #include <math.h>
 3 
 4 double mysqrt(double n, double x0)
 5 {
 6     double x1;
 7     double y;
 8     
 9     x1 = (x0 + n/x0)/2.0;
10     
11     if (fabs(x1-x0) >= 0.00001)
12         y = mysqrt(n, x1);
13     else
14         y = x1;
15     
16     return y;
17 }
18 
19 int main(void)
20 {
21     printf("sqrt(2) = %lf\n", mysqrt(2.0, 1.0));
22     
23     return 0;
24 }

sqrt(2) = 1.414214