C++ 错误：“被调用的对象类型‘int’不是函数或函数指针”

Question

I am attempting to write a quadratic equation calculator in C++, and I keep running into this error. See if you can figure out why: (the error occurs on the 'g =' line)

#include <cmath>
#include <iostream>
using namespace std;
int main(){
    int a,b,c,d,e,f,g;
    cout<<"Enter 'A' value:";
    cin>>a;
    cout<<"Enter'B' value:";
    cin>>b;
    cout<<"Enter 'C' value:";
    cin>>c;
    e = ((b * b) - (4 * (a*c)));
    d = sqrt(e);
    f = ((-b) + d) / (2 * a);
    g = ((-b) - d) / (2 * a);
    if(d > 0){
        cout<<"One solution is: "<<f<<endl;
        cout<<"The other solution is: "<< g <<endl;
    }
    else if(d == 0){
        cout<<"Your 1 solution is: "<< f <<endl;
    }
    else{
        cout<<"No real solutions!"<<endl;
    }
}

Any help is appreciated!

Answer 1

The square root function will return floating point values, so you should use a floating point variable like double to store the result.

#include <cmath>
#include <iostream>
using namespace std;
int main(){
    int a,b,c,e;
    double d,f,g;
    cout<<"Enter 'A' value:";
    cin>>a;
    cout<<"Enter'B' value:";
    cin>>b;
    cout<<"Enter 'C' value:";
    cin>>c;
    e = ((b * b) - (4 * (a*c)));
    d = sqrt(e);
    f = ((-b) + d) / (2 * a);
    g = ((-b) - d) / (2 * a);
    if(d > 0){
        cout<<"One solution is: "<<f<<endl;
        cout<<"The other solution is: "<< g <<endl;
    }
    else if(d == 0){
        cout<<"Your 1 solution is: "<< f <<endl;
    }
    else{
        cout<<"No real solutions!"<<endl;
    }
}

Answer 2

The problem is that the square root function returns a floating point decimal, and you are trying to combine it with an integer. For example, 1 - 2.0. Both of the values have to be floating point decimals, so you should change "int" to "double" on line 5.