尝试插入 std::set 时出现“'operator<' 不匹配" [英] “no match for 'operator<'” when trying to insert to a std::set

问题描述

我正在使用 gcc 4.3.3 尝试编译以下代码:

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 < other.x; }  
testStruct(int x_, int y_) {  
    x = x_;  
    y = y_;  
}  
};  


int main() {
multiset<testStruct> setti;  
setti.insert(testStruct(10,10));  
return 0;  
}

我收到此错误:
/usr/include/c++/4.4/bits/stl_function.h|230|错误:在‘__x <’中不匹配‘operator<’__y'
我怀疑我没有像应该做的那样做运算符重载，但我无法查明确切的问题.我在这里做错了什么?

I get this error:
/usr/include/c++/4.4/bits/stl_function.h|230|error: no match for ‘operator<’ in ‘__x < __y’
I suspect I'm not doing the the operator overloading as it should be done, but I just can't pinpoint the exact problem. What am I doing wrong here?

推荐答案

操作符必须是 const 并取 const 引用:

The operator must be const and take a const reference:

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

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