69 Sqrt(x)

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Implement int sqrt(int x).

Compute and return the square root of x.

int sqrt(int x) {    double ans    = x;    double delta  = 0.0001;    while (fabs(pow(ans, 2) - x) > delta) {        ans = (ans + x / ans) / 2;    }    return ans;}

根据公式：ans = (ans + x / ans) / 2  不断的迭代计算直到达到初始设定的阈值。