Question

I am trying to set up an array of string that’s size and content dependent on the users input. I am getting an error declaring my array, it says the variable for the size is not the right type. I’ve spent a few hours on this just thought I’d ask.

Here’s my code:

#include <iostream>
#include <string>

using namespace std;

int main()
{
    cout << "Enter number of names /n";
    int a;
    cin >> a;
    string namesArray[a];         //Error is here.
    for( int i=0; i<a; i++) {
        string temp;
        cin >> temp;
        namesArray[i] = temp;
    }

    for( int j=0; j<a; j++) {
        cout << "hello " << namesArray[j] << "/n";

    }
    return 0;
}

The error is at string namesArray[a];

Answer 1

An array needs to have a compile-time value for its size. Your code wont compile because a is not a compile-time constant.

Better use std::vector:

#include <iostream>
#include <string>
#include <vector>   // <-- Must be included

using namespace std;

int main()
{

    cout << "Enter number of names /n";
    int a;
    cin >> a;

    vector<string> namesArray;    // HERE!!!

    for( int i=0; i < a; i++) {
        string temp;
        cin >> temp;
        namesArray.push_back(temp);   // Notice the difference
    }

    for( int j=0; j<a; j++) {
        cout << "hello " << namesArray[j] << "/n";
    }

    return 0;
}