CODEWITHSUNDEEP
c++arraysc++11stl
user3196828
user3196828

Reputation: 42

Can't convert std::array to int?

I am just learning c++ and am attempting to understand arrays.. So forgive my ignorance on what's wrong here.

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

void readArray(int *readfile, int ArraySize){
    int Interator;
    for(Interator = 1; Interator < ArraySize; Interator++){
        cout << " " << readfile[Interator];
    }
}

int main(){
    std::array<int, 5> array2={{1, 2, 3, 4, 5}};
    readArray(array2, array2.end());
}

Error: Can't Convert 'std::array' to 'int*' for arg '1'to void 'readArray'

How would I fix this?

Upvotes: 0

Views: 3479

Answers (2)

karastojko
karastojko

Reputation: 1181

You cannot convert std::array to int* as compiler says. For such conversion you can use plain old array:

void readArray(int *readfile, int ArraySize)
{
    int Interator;
    for(Interator = 0; Interator < ArraySize; Interator++)
    {
        cout << " " << readfile[Interator];
    }
}

int main()
{
    //std::array<int, 5> array2={{1, 2, 3, 4, 5}};
    int array2[] = {1, 2, 3, 4, 5};
    readArray(array2, 5);
}

Also, Interator is changed to start from zero. If you need std::array then use std::array::begin() and std::array::begin():

void readArray2(const std::array<int, 5>& a)
{
    for (auto elem : a)
        cout << " " << elem;
}

int main()
{
    std::array<int, 5> array2={{1, 2, 3, 4, 5}};
    //int array2[] = {1, 2, 3, 4, 5};
    readArray2(array2);
}

Upvotes: 2

Jack
Jack

Reputation: 133567

Just browse some reference to discover that std::array has a T* data() and a constexpr size_type size() which can and should be used for that purpose.

But this is a poor solution. The best solution would be to use iterators directly, eg:

template <typename T> void readArray(const T& data) {
  for (const auto& element : data)
    cout << element;
}

std::array<int, 5> data1 = { 1, 2, 3, 4, 5};
readArray(data1);
std::vector<int> data2 = {1, 2, 3, 4, 5};
readArray(data2);
std::list<int> data3 = {1, 2, 3, 4, 5};
readArray(data3);

Which would expect T to be a type that has proper begin and end() overloads.

It makes no sense to tag questions with C++11 if you try to use C solutions,

Upvotes: 3

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