在类中向量成员的奇怪现象 [英] A strange phenomenon of vector member in a class

问题描述

所有的头文件包括

class Test{ 
public:
    vector<int> vector_int(10);
    Test(int num);
    ~Test();
};

Test::Test(int num){
    cout << "constructor employed" <<endl;
    vector<int> vector_int;
    for (int i = 0; i < num; i++){
        vector_int.push_back(i);
    }
    cout<<"The size is " << vector_int.size()<<endl;
}

int main(){
    int num = 10;
    Test* a = new Test(10);
    cout<< a->vector_int.size()<< " is the size"<<endl;
    return 0;
}

结果：构造函数采用
大小为10

Result: constructor employed The size is 10

0是大小

在我看来，这些大小应该是相同的。还使用构造函数。

It seems to me that these sizes should be the same. The constructor is also employed. What is the problem then?

推荐答案

您正在隐藏类成员变量 vector_int

You are shadowing the class member variable vector_int with a local variable of the same name in the constructor.

删除向量< int>中的同一个局部变量。 vector_int; 从构造函数，它应该按预期工作。

Remove the line vector<int> vector_int; from the constructor and it should work as expected.

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