P4.06 P73231 Maximum of four integer numbers

#include <iostream>
using namespace std;

int max4(int a, int b, int c, int d) {
    int x;
    if(a>=b&&a>=c&&a>=d) x=a;
    else if (b>=a&&b>=c&&b>=d) x=b;
    else if (c>=a&&c>=b&&c>=d) x=c;
    else x=d;
    return x;}

int main(){
    int a,b,c,d;
    cout<<"A=";
    cin>>a;
    cout<<"B=";
    cin>>b;
    cout<<"C=";
    cin>>c;
    cout<<"D=";
    cin>>d;
    cout<<endl<<max4(a,b,c,d)<<endl;

    }