how do I pass a string array to a function in C++

Question

2.50/5 (2 votes)

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i tried this code

C++

#include<iostream>
#include<conio.h>
#include<string.h>
using namespace::std;
// The called function //
void rando1(int a[])
{
    for(int j=0;j<5;j++)
    {
    
        cout<<a[j]<<endl;
        cout<<endl;
    }
}

main()
{
    int arr[4];
    for(int i=0;i<5;i++)
    {
        cout<<"Enter 5 numbers: ";
        cin>>arr[i];
    }
    cout<<endl;
    // The calling function //
    rando1(arr);
    getch();
}

it works

but i also tried changing the data type int into a string but i didnt work. how can i pass string arrays to a function?

Thank you for helping

Posted 6-May-15 5:01am

Reuben Cabrera

Updated 6-May-15 5:24am

Richard MacCutchan

v2

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Comments

Sergey Alexandrovich Kryukov 6-May-15 11:25am

Where are your string objects and what's the problem? You can pass it the same way as any other objects or arrays of objects...
—SA

Reuben Cabrera 6-May-15 18:50pm

i just changed the data type in the program from int to string. didnt work.

Albert Holguin 6-May-15 18:51pm

Upvoted the question because it's a legitimate question and the OP is actually trying. Not sure who/why it was downvoted. (+4)

2 solutions

Solution 2

Modern C++ can be quite expressive:

C++

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

template <typename T, size_t N> void show_array( array <T,N> & a)
{
  for (const auto & x : a) cout << x << endl;
}

int main()
{

  array<int,3> ai = { -3 ,17, 0};
  array<string,2> as= {"foo", "bar"};

  show_array(ai);
  show_array(as);
}

A more (more) traditional approach:

C++

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

void show_int_array(int ai[], size_t size)
{
  for (size_t n = 0; n < size; ++n)
    cout << ai[n] << endl;
}
void show_string_array(string as[], size_t size)
{
  for (size_t n = 0; n < size; ++n)
    cout << as[n] << endl;
}


int main()
{
  int ai[] = {3, -5, 7};
  string as[] = { "foo", "bar" };

  show_int_array(ai, sizeof(ai)/sizeof(ai[0]));
  show_string_array(as, sizeof(as)/sizeof(as[0]));
}

The code redundancy of show_int_array and show_string_array immediately suggests the usage of a template:

C++

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

template <typename T> void show_array(T a[], size_t size)
{
  for (size_t n = 0; n < size; ++n)
    cout << a[n] << endl;
}

int main()
{
  int ai[] = {3, -5, 7};
  string as[] = { "foo", "bar" };

  show_array(ai, sizeof(ai)/sizeof(ai[0]));
  show_array(as, sizeof(as)/sizeof(as[0]));
}

'Minimalist' approach

C++

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

int main()
{
  int ai[] = {3, -5, 7};
  string as[] = { "foo", "bar" };

  for (auto x : ai) cout << x << endl;
  for (auto s : as) cout << s << endl;
}

Posted 6-May-15 6:04am

CPallini

Updated 6-May-15 21:58pm

v5

Comments

Sergey Alexandrovich Kryukov 6-May-15 15:07pm

Nice, a 5 (only better remove all those <h1>...)
—SA

CPallini 6-May-15 15:44pm

Thak you.
I tried my best in order to remove them. In fact they don't even appear in the code while I'm editing, I see them only after the submit.

Afzaal Ahmad Zeeshan 6-May-15 15:56pm

There you go CPallini. Hope you don't mind the imminent edit. ;)

CPallini 6-May-15 16:11pm

Thank you very much.

Sergey Alexandrovich Kryukov 6-May-15 16:43pm

I can see some glitched in posting these days, but usually the artifacts can be removed after next couple of attempts. :-)
—SA

Albert Holguin 6-May-15 18:49pm

Even though I like your solution... not sure it's well suited for a newbie. +4 :)

CPallini 7-May-15 3:30am

Yes, I see that. Thank you.

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Richard MacCutchan · Accepted Answer · 2015-05-06T05:29:00

Solution 1

You are corrupting memory with this code. The elements of a 4 element array lie in the range [0..3] not [0..5]. And passing strings is exactly the same as passing ints, just make sure the function parameter type is correct, e.g.

C++

void rando1(string a[])
{
    for(int j = 0; j < 4; j++)
    {
        cout << a[j] << endl;
        cout << endl;
    }
}

Posted 6-May-15 5:29am

Richard MacCutchan

Comments

Afzaal Ahmad Zeeshan 6-May-15 11:33am

+5 :)

CPallini 6-May-15 12:04pm

5.

Albert Holguin 6-May-15 18:52pm

+5

Reuben Cabrera 6-May-15 18:53pm

doesn't work :(

Richard MacCutchan 7-May-15 3:59am

What doesn't work?

Reuben Cabrera 7-May-15 7:32am

the code you provided

Richard MacCutchan 7-May-15 7:53am

That is a particularly useless comment, because the code I provided is only part of the issue. For example, did you implement it correctly? Please edit your question and show all the code and any error messages or exceptions that occur.