Program to find maximum of three numbers

#include<iostream.h>
#include<conio.h>
int maximum(int a,int b, int c);
void main()
{
    int x,y,z,max;
    cout<<"enter three numbers ";
    cin>>x>>y>>z;
    max=maximum(x,y,z);
    cout<<"maximum is "<<max;
    getch();
}
int maximum(int a,int b,int c)
{
    if(a>b)
        if(a>c)
            return a;
        else
            return c;

    else
        if(b>c)
            return b;
        else
            return c;

}