Vector of an array of structs resets strings to be blank. C++

November 13, 2022

So I’m having a very confusing issue where I’m attempting to print a string from a vector of arrays of structs to the console. Integers print just fine however strings stored within these structs get set to "". I have no idea what’s going on here but after setting up a test as shown bellow this issue is still persisting. Any help figuring this out would be greatly apricated.

Should also mention I’m still new to c++ so I apologise if the issue here is something simple.

#include <iostream>
#include <string>
#include <vector>
#include "Header.h"

//Test struct
struct testStruct
{
    string testString;
    int testInt;
};

testStruct testArray[1] = {
    testArray[0] = {"String works", 69}
};

int main()
{
    srand(time(NULL));
    
    vector < testStruct > test;
    test.push_back({ testArray[0] });
    cout << test[0].testString << "\n"; // prints "", should print "String works"
    cout << test[0].testInt << "\n"; // prints 69
    
    characterCreation();
    checkPlayerStats();
    introduction();

    return 0;
}

>Solution :

This surprised me. The following code is legal (syntactically at least)

testStruct testArray[1] = {
    testArray[0] = {"String works", 69}
};

but if you replace it with the sensible version

testStruct testArray[1] = {
    {"String works", 69}
};

then your program works as expected.

I expect your version has undefined behaviour because you are assigning (here testArray[0] = ...) to an array element that has not yet been created.