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#include<iostream>
#include<queue>
using namespace std;
class A
{
public:
int a;
};
int main()
{
queue<A> q;
A aa;
aa.a=3;
q.push(aa);
A &bb=q.front();
bb.a=4;
cout<<aa.a<<" "<<bb.a<<endl; // 输出 3 4?
return 0;
}
为什么没有改aa对象的值呢?
q.push(aa); //q keep a copy of aa, not a reference to aa