problems with printing 2d array from print function

Question

I'm trying to fill and print with 2d array, yet every time I try to compile it says undeclared identifier c. And points an arrow at the c in the print function. I tried declaring it many ways yet for some reason it will not work.

#include <iostream>

using namespace std;

void print(char x[][c], int r)
{
    for(int r  = 0; r < 25; r++)
    {
        for(int c = 0; c < 25; c++)
        {
          cout << x[r][c]; 
        } 
        cout << endl;    
    } 
}

int main()
{
    void print(char x[][c], int r);

    char p[25][25];

    for(int r = 0; r < 25; r++)
    {

        for(int c = 0; c < 25; c++)
        {
            if(r==0)p[r][c]='x';
            else    p[r][c]='o';
        }    
    }   

    print(p[25][25]);


    return(0);
}

what is c?? void print(char x[][c], int r) ?? and in this line void print(char x[][c], int r); — Alon
– Alon, Commented Jul 23, 2015 at 22:33
What means char x[][c]? Particularly "c"? Try to understand compiler error. — Adrian Krupa
– Adrian Krupa, Commented Jul 23, 2015 at 22:34
Your code is wrong on so many levels... What do you want to achieve? Could you write the output you want? — nsilent22
– nsilent22, Commented Jul 23, 2015 at 22:34

Vlad from Moscow · Accepted Answer · 2015-07-23 22:40:14Z

2

Write the following way

#include <iostream>

using namespace std;


const size_t ROWS = 25;
const size_t COLS = 25;

void print(char x[][COLS], size_t r )
{
    for ( size_t i  = 0; i < r; i++ )
    {
        for ( size_t j = 0; j < COLS; j++ )
        {
          cout << x[i][j]; 
        } 
        cout << endl;    
    } 
}

int main()
{
    char p[ROWS][COLS];

    for ( size_t i = 0; i < ROWS; i++ )
    {
        for ( size_t j = 0; j < COLS; j++ )
        {
            if ( i == 0 ) p[i][j] = 'x';
            else p[i][j] = 'o';
        }    
    }   

    print( p, ROWS );


    return(0);
}

Another approach is to define the function the following way

void print( char ( &x )[ROWS][COLS] )
{
    for ( size_t i  = 0; i < ROWS; i++ )
    {
        for ( size_t j = 0; j < COLS; j++ )
        {
          cout << x[i][j]; 
        } 
        cout << endl;    
    } 
}

and call it like

    print( p );

edited Jul 23, 2015 at 22:40

answered Jul 23, 2015 at 22:35

Vlad from Moscow

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2 Comments

Soner from The Ottoman Empire Over a year ago

can you explain another approach ? I don't know char ( &x )[ROWS][COLS]

Vlad from Moscow Over a year ago

@itsnotmyrealname It is a declaration of a reference to a 2D array. For example if you have a declaration int x = 10; then a reference to x is declared like int &rx = x; If you have a 1D array int a[10]; then a reference to the array is declared like int ( &ra )[10] = a;

Buddy · Accepted Answer · 2015-07-23 22:34:52Z

0

Try this:

#include <iostream>

using namespace std;

void print(char x[25][25])
{
    for(int r  = 0; r < 25; r++)
    {
        for(int c = 0; c < 25; c++)
        {
          cout << x[r][c]; 
        } 
        cout << endl;    
    } 
}

int main()
{
    char p[25][25];

    for(int r = 0; r < 25; r++)
    {
        for(int c = 0; c < 25; c++)
        {
            if(r==0)p[r][c]='x';
            else    p[r][c]='o';
        }    
    }   

    print(p);

    return(0);
}

answered Jul 23, 2015 at 22:34

Buddy

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