what the...

#include <iostream>
#include <math.h>
using namespace std;
float integral(float a)
{
    float s;
    if (0 < a <= 1 || a <= 0)
    {
        if (a <= 0)
        {
            s = 0;
        }
        if(a>0 && a<=1)
        {
            s = a;
        }
    }
    else
    {
        s = pow(a, 3);
    }
    return s;
}

int main()
{
    float a, s;
    cout << "a= "; cin >> a;
    s = integral(a);
    cout<<"∫(a) = " << s <<"\n";
    return 0;
}