Question

I have come up with some code and it does not compile.

Error 1 error C2296: ‘^’ : illegal, left operand has type ‘double’
2 IntelliSense: expression must have integral or enum type

The code I was able to come up with is as follows:

#include<iostream>
#include<cmath>
using namespace std;

void getnumbers();
void showmean();
void showdev();

double x1, x2, x3, mean, dev;

void getnumbers()
{
    cout<<"Please enter three numbers\n";
    cin>>x1,x2,x3;
}

void showmean()
{
    mean=(x1+x2+x3)/3;

    cout<<"The mean of"<<x1<<", "<<x2<<", "<<x3<<" is "<<mean<<endl;
}

void showdev()
{
    dev=sqrt((x1 - mean)^2) + (x2 - mean)^2 + (x3 - mean)^2/3;

    cout<<"The standard deviation of"<<x1<<", "<<x2<<", "<<x3<<" is "<<dev<<endl;
}

int main()
{
    getnumbers();
    showmean();
    showdev();

    system("pause");

    return 0;
}

Answer 1

1. You can’t take powers like that in C++

   • Use std::pow() or x*x for mathematical x²

2. For multiple inputs it’s cin >> x1 >> x2 ...etc

3. In your SD equation, your close paren is in the wrong spot I think, mathematically.

   • it should be SD = sqrt( (x*x + y*y) / z ). Your close paren makes it x + y*y/3 (or y^2/3, forget precedence)