#面试 #数字开根号

sqrt_float.cpp

float sqrt_float(float x) {
    if (x < 0) {
        return -1;
    }

    float left = x/2, right = x;
    if (x < 0.5) {
        left = 0;
        right = x;
    }

    float eps = 1e-5;
    while (right - left > eps) {
        float mid = (left + right) / 2.0;
        float mid2 = mid * mid;

        if (abs(mid2 - x) < eps) {
            return mid;
        }

        if (mid2 < x) {
            left = mid;
        } else {
            right = mid;
        }
    }
    return right;
}