C++ 读访问冲突，结构向量

Question

I have a "program" and i want to behave the way i would like to, but the situation is:

I want to create a vector of structs with max element equal to 25 and then inicialize every struct member (this time only the name) through a function. My problem is i get an exception error: ( Exception thrown: read access violation ) and i have no idea what i did wrong. (and the program needs to end at the name input with one "-" character.)

The code:

#include <iostream>
#include <string>
#include <ctime>
#include <cstdlib>
#define MAXstudent 25
#include <sstream> 
#include <vector>
using namespace std;

struct student {
    string name; 
};

void get_input(vector<student>& student_group) {

    for (int i = 0; i < MAXstudent; i++) {

       //name
       string temp_variable = "";
       cout << "Student name: ";
       getline(cin, temp_variable);
       if (temp_variable != "-") {
           //student_group.push_back(student());
           student_group[i].name = temp_variable;
           cout << endl;
       }
       else {
           student_group.push_back(student());
           student_group[i].name = temp_variable;
           break;
       }
   }
}

void show_solution (vector<student>& student_group) {
    int i = 0;
    while (student_group[i].name != "-") {
        cout << "\nSolutions: " << endl;

        cout << endl << i + 1 << '.' << "kert name: " << student_group[i].name;
        i++;
    }

}

int main() {
    srand(time(0));
    vector<student>student_group[MAXstudent];
    get_input(student_group[MAXstudent]);
    show_solution (student_group[MAXstudent]);
}

Answer 1

Your main should be:

int main() {
    srand(time(0));
    vector<student>student_group(MAXstudent); // create one vector with MAXstudent elements in it
    //vector<student>student_group[MAXstudent]; - this creates MAXstudent vectors with 0 elements in each
    get_input(student_group);
    show_solution (student_group);
}

In your code you created array of vectors and used a vector with out of bounds of that array. You should understand what you are doing instead of creating random code and expecting it to work someway.

Answer 2

This is what makes the error

get_input(student_group[MAXstudent]);
show_solution (student_group[MAXstudent]);
vector<student>student_group[MAXstudent];

Change them to

get_input(student_group);
show_solution (student_group);
vector<student>student_group(MAXstudent);

The student_group[MAXstudent] atempts to reach the element of index 25 (ie) the 26th element while your vector is 25 element.

Note that the vector is just an object containing your elements (container), so pass it as mentioned and then you can access your elements in the function body by their indecis.

I think you need to read more about std::vector s