“no match for 'operator<'” when trying to insert to a std::set

Question

I\'m using gcc 4.3.3 to try to compile the following code:

struct testStruct {  
int x;  
int y;  
bool operator<(testStruct &other) { return x < o         


        

Answer 1

The operator must be const and take a const reference:

bool operator<(const testStruct &other) const { return x < other.x; }