我學習如何使用函數,所以我創建了一個,我不明白爲什麼我的計數器變量在程序結束時爲0。爲什麼我的函數成員變量「重置」? (C++)
這裏的代碼:
#include"stdafx.h"
#include<iostream>
#include<vector>
#include<algorithm>
#include<map>
#include<list>
using namespace std;
class myFunctor {
public:
myFunctor():counter(0) {}
void operator()(int i) { cout << "in the functor: " << i ; counter++; cout << " counter=" << counter << endl; }
int getCounter() const { return counter; }
private:
int counter;
};
int main()
{
vector<int> v{ 1,2,3,4,5,6,7,8,9,10 };
myFunctor f;
for_each(v.begin(), v.end(), f);
cout << "counter=" << f.getCounter() << endl;
return 0;
}
這裏是什麼結果得出:
in the functor: 1 counter=1
in the functor: 2 counter=2
in the functor: 3 counter=3
in the functor: 4 counter=4
in the functor: 5 counter=5
in the functor: 6 counter=6
in the functor: 7 counter=7
in the functor: 8 counter=8
in the functor: 9 counter=9
in the functor: 10 counter=10
counter=0
你永遠不actualy修改什麼,但臨時副本,爲什麼你會想到什麼嗎? –