我在理解C++ clear函數的行爲時,遇到了一些困難,當應用於向量時。vector :: clear in C++
我試圖編譯並運行以下功能:
#include <iostream>
#include <vector>
using namespace std;
int main()
{
unsigned int i;
vector<int> myvector;
myvector.push_back (1);
myvector.push_back (2);
myvector.push_back (3);
cout << "myvector contains:";
for (i=0; i<myvector.size(); i++) cout << " " << myvector[i];
myvector.clear();
myvector.push_back (11);
myvector.push_back (12);
cout << "\nmyvector contains:";
for (i=0; i<myvector.size(); i++) cout << " " << myvector[i];
cout << endl;
cout << " entry3 = " << myvector[2]<<endl;
return 0;
}
這是輸出:
myvector contains: 1 2 3
myvector contains: 11 12
entry3 = 3
這怎麼可能是向量的第三項的信息,也沒有清除矢量時已被刪除?
operator []不是長度驗證索引。用.at(n)嘗試相同的操作,看看會發生什麼。 – WhozCraig