预定义的squareroot函数,不使用C中的math.h中的sqrt()

#include<stdio.h>

double squareroot(double x) {
    if (x < 0) {
        return -1; // 返回-1表示输入的数值不合法
    }
    double left = 0, right = x;
    while (left <= right) {
        double mid = (left + right) / 2;
        if (mid * mid == x) {
            return mid;
        } else if (mid * mid < x) {
            left = mid;
        } else {
            right = mid;
        }
    }
    return right; // 返回right表示找到的最接近的平方根值
}

int main() {
    double x = 9;
    double result = squareroot(x);
    printf("The square root of %f is %f\n", x, result);
    return 0;
}