When comparing two addresses, why is that an address is no less than and no more than another address, but they're not equal?

Question

I write a code (in my Windows 11, with Embarcadero C++ and using GNU G++17) as follows:

#include<bits/stdc++.h>
using namespace std;
int main(){
    int a,b;
    cout<<&a+1<<endl<<&b<<endl;
    cout<<(&a+1==&b)<<endl;
    return 0;
}

I suppose that, if &a+1 and &b gives the same address value, the statement &a+1==&b will returns 1. However, it returns a 0.

0x78fe1c
0x78fe1c
0

---

To clarify this issue, I added some lines of code.

#include<bits/stdc++.h>
using namespace std;
int main(){
    int a,b;
    cout<<&a+1<<endl<<&b<<endl;
    cout<<(&a+1<=&b)<<endl;
    cout<<(&a+1>=&b)<<endl;
    cout<<(&a+1==&b)<<endl;
    cout<<(&a+1!=&b)<<endl;
    return 0;
}

But the result becomes more confusing:

0x78fe1c
0x78fe1c
1
1
0
1

It means that, &a+1 is no more than &b and no less than it. In the meantime they are not equal. But why?