C++

Forum

 
assigning multidimensional array

hellcoder (114)
what is wrong here? i am trying to assign hii to second row of array!

1
2
3
4
5
6
7
8
9
10
11
12
 
 #include <iostream>

using namespace std;

int main()
{
char a[2][5];
*(a+1)="hii";
//cout<< a[1]<<endl;
    return 0;
}
Last edited on
closed account (N36fSL3A)
why not:

1
2
3
4
5
6
7
 
int main()
{
    char a[2][5];
    a[1] ="hii";
    //cout<< a[1]<<endl;
    return 0;
}


I don't know if this will actually work, I don't use md arrays.

By the way: http://www.cplusplus.com/forum/articles/17108/
Chriscpp (368)
1
2
3
4
5
6
7
8
9
10
11
 
#include <iostream>
#include <string>
using namespace std;

int main()
{
    string a[2][5];
    a[1][1]="hii";
    cout<< a[1][1]<<endl;
    return 0;
}
andywestken (4094)
@hellcoder

When you declare a[2][5] you are declaring an array with 2 elems each of which is an array of 5 chars.

With a char array you have to copy the data in, using strcpy (or equivalent.)

1
2
 
char a[5];
strcpy(a, "Hi!");


The same rules apply here:

1
2
3
4
5
6
7
8
9
10
11
 
#include <iostream>

using namespace std;

int main()
{
    char a[2][5];
    strcpy(a[1], "hi!"); // copy "hi!" into second buffer in array
    cout<< a[1] <<endl;
    return 0;
}


I altered *(a+1) to a[1] as I think it reads more clearly, esp. when dealing with arrays.

Chriscp has replaced your 1D array of char buffers with a 2D array of std::string elements.

Did you want a 1D array? Or a 2D array??

Andy
Last edited on
hellcoder (114)
@lumpkin that is the same thing! both ain't works
Last edited on
giblit (3750)
hellcoder wrote:
ain't works


Can you please explain?
Last edited on
hellcoder (114)
edited!
hellcoder (114)
@andy
2-D array!
n thanks!
hellcoder (114)
@Chriscpp
that is not working!
vlad from moscow (6539)
@hellcoder

@Chriscpp
that is not working!


He made a typo. Should be

1
2
3
4
5
6
7
8
9
10
11
12
13
 
#include <iostream>
#include <string>

int main()
{
    std::string a[2];

    a[1] = "hii";

    std::cout << a[1] << std::endl;

    return 0;
}
Last edited on
Chriscpp (368)
vlad it works for me even this

1
2
3
4
5
6
7
8
9
10
11
12
13
 
#include <iostream>
#include <string>
using namespace std;

int main()
{
    string a[2][5];
    a[1][1]="hii";
    a[1][2]="hello";
    cout<< a[1][1]<<endl;
    cout<< a[1][2]<<endl;
    return 0;
}
vlad from moscow (6539)
@Chriscpp

vlad it works for me even this


Yes it can work but you complicated the code. It can be written more simpler as I showed. Your code does not correspond to the original declaration of the array as

char a[2][5];

This array is designed to store two character strings. So the more or less equivalent code will be

std::string a[2];
Last edited on
giblit (3750)
Yeah but [0][0->4] are undefinied , [1][0] undeifined , and [1][3&4] are undefined but your example should help them out.
Curious as to why you choose those ones I would of just did something like
1
2
3
4
5
6
7
8
9
10
11
12
 
#include <iostream>
#include <string>

int main()
{
    std::string s_2d_array[ 1 ][ 2 ] = { "hello" , "hii" };
    s_2d_array[ 0 ][ 0 ] = "hii";
    s_2d_array[ 0 ][ 1 ] = "hello";
    std::cout << s_2d_array[ 0 ][ 0 ] << std::endl;
    std::cout << s_2d_array[ 0 ][ 1 ] << std::endl;
    return( 0 );
}

*edit had a typo.
Last edited on
andywestken (4094)
This array is designed to store two character strings.

Thing is, going by the response to my question about 1D or 2D,

hellcoder wrote:
@andy
2-D array!
n thanks!

it appears that it's the original code which is wanting.

Andy
Topic archived. No new replies allowed.