“变量周围的堆栈已损坏”。如何确定数组的大小？

Question

I am supposed to write a simple program that will allow the user to input their last name into the program. The program will then output their last name onto the screen. However, when I run the program I see the error "Stack around the variable last was corrupted". Luckily this is a very short program, however, I am still confused what exactly is causing the issue to occur.

I have tried changing the size of the array from the number of elements in it to the number of bytes in it. I attempted this since the array is made up of characters and not integers.

The assignment states that the entered array may not be larger than 10 (composed of 9 characters). This is why the global variable "MAX" is present.

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

const int MAX = 10;

int main()
{ 
    char last[MAX];
    int size = 0;

    cout << "Enter you last name with no more than 9 characters: "
             << endl;
    cin >> last[MAX];

    size = sizeof(last);

    cout << "This is your last name: " << endl;
    cin >> last;

    return 0;
}

Answer 1

char last[MAX];
cin >> last[MAX];

The array has MAX element, and the index starts at 0. Which means the last element is at index MAX-1;

Stack around the variable last was corrupted

This is because you are accessing last[MAX] , which is past the allocated memory for the array.

It should be

cin >> last;

Answer 2

cin >> last[MAX];

should be

cin >> last;

but even better use std::string instead of char array.

last[MAX] does out of bound access, (and would only allow to retrieve one char)