Default comparisons(since C++20)

 

C++

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Assignment operators: a=b, a+=b, a-=b, a*=b, a/=b, a%=b, a&=b, a|=b, a^=b, a<<=b, a>>=b

Increment and decrement: ++a, --a, a++, a--

Arithmetic operators: +a, -a, a+b, a-b, a*b, a/b, a%b, ~a, a&b, a|b, a^b, a<<b, a>>b

Logical operators: a||b, a&&b, !a

Comparison operators: a==b, a!=b, a<b, a>b, a<=b, a>=b, a<=>b(C++20)

Member access operators: a[b], *a, &a, a->b, a.b, a->*b, a.*b

Other operators: a(...), a,b, a?b:c

Default comparisons(C++20)

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User-defined conversion

 

Provides a way to request the compiler to generate consistent relational operators for a class.

In brief, a class that defines operator<=> automatically gets compiler-generated operators ==, !=, <, <=, >, and >=. A class can define operator<=> as defaulted, in which case the compiler will also generate the code for that operator.

class Point {
 int x;
 int y;
public:
 auto operator<=>(const Point&) const = default;
 // ... non-comparison functions ...
};
 
Point pt1, pt2;
if (pt1 == pt2) { /*...*/ } // ok
set<Point> s; // ok
s.insert(pt1); // ok
if (pt1 <= pt2) { /*...*/ } // ok, makes only a single call to <=>