16th Week "C + + Language foundation" practice reference--the exception in the square root

Problem Description:

"Exception in item 1-square root"
Write a program that asks for the square root of the number of inputs. Set exception handling, and use the exception handling mechanism to give hints when entering negative numbers.

Code implementation:

#include <iostream> #include <cstdio> #include <cmath>using namespace Std;int main () {    double A;    try{        printf ("Please enter a number:");        scanf ("%lf", &a);        Double b;        if (a>0)        b=sqrt (a);        else throw A;        cout<<a<< "The square root is" <<b;    }    catch (double) {        printf ("Input Error! ");    }    return 0;}

Operation Result:

16th Week "C + + Language foundation" practice reference--the exception in the square root