c++野指针

野指针分类

• 指针定义的时候，没有进行初始化

int *p;
cout << "p = "<<p <<"  *p = "<<(*p)<<endl;

• 指针指向了动态分配的内存，在内存被释放后，指针不会置空，但是指针的指向已经失效

int *p = new int(3);
cout << "p = "<<p <<"  *p = "<<(*p)<<endl;
delete p;
cout << "p = "<<p <<"  *p = "<<(*p)<<endl;

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• 指针指向的变量已超越变量作用域

#include <iostream>
#include<string>
using namespace std;

int* fun() {
    int a = 3;
    cout << "a = "<<a <<"  &a = "<<&a<<endl;
    return &a;
}

int main() {
    int *p = fun();
    cout << "p = "<<p <<"  *p = "<<(*p)<<endl;
    return 0;
}

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规避野指针

• 指针在定义的时候，如果么有指向，就初始化nulptr
• 动态内存被释放后，将其置为nullptr
• 函数不要返回局部变量的地址