How do I print an array row-by-row in C++?

Question

I'm simply trying to print the first seven rows of a two dimensional array. Whats wrong with my code?

I keep getting the seven rows in one long row instead of their own individual rows. Everything I've googled/read leads me to believe that my code is correct, but it still doesn't work. I've tried using \n and endl;, but that sends it down, each integer on its own line instead of the lines ending at 15.

//these are the declarations
int row = 12;
int col = 15;
int someArray[row][col];
for (row = 0; row < 12; row++)
    for (col = 0; col < 15; col++)
        someArray[row][col] = col;

//this is where my problem is
for (int row = 0; row < 7; row++)
    for (int col = 0; col < 15; col++)
        cout << someArray[row][col] << " "

I need the output to be the first seven rows of this array, separated into their respective lines of output, but upon compilation and execution, the output is one long line of these seven rows.

I've tried a newline character inside the last pair of quotations, but the output then gave every integer its own line, not the whole row. — Birch Poirier, Jun 09 '19 at 17:00
This `nt someArray[row][col];` is not valid C++ - the dimensions of arrays must be compile-time constants. — , Jun 09 '19 at 17:00
Print newline character in the end of the first loop i.e after the second loop. — muaz, Jun 09 '19 at 17:04
Consider enabling more compiler checks: (2x) error: ISO C++ forbids variable length array ‘someArray’ [-Werror=vla] (1x) warning: declaration of ‘row’ shadows a previous local [-Wshadow] (1x) warning: declaration of ‘col’ shadows a previous local [-Wshadow] — 2785528, Jun 09 '19 at 17:42

score 0 · Answer 1 · answered Jun 09 '19 at 20:53

Add new line character:

cout << endl;

Or

cout << "\n";

Now your code should look like:

for (int row = 0; row < 7; row++){
    for(inr col = 0; col < 15; col++){
         cout << someArray[row][col] << " ";
    }
    cout << "\n"; // or cout << endl;
}

DSC · Accepted Answer · 2019-06-09T17:09:12.180

-1

Add a newline character:

for (int row = 0; row < 7; row++){
    for (int col = 0; col < 15; col++){
        cout << someArray[row][col] << " ";
    }
    cout << endl;
}

edited Jun 09 '19 at 17:09

answered Jun 09 '19 at 17:04

DSC

1,153
7
21

1

You might want to add braces, otherwise this won’t work properly – Sami Kuhmonen Jun 09 '19 at 17:06
@SamiKuhmonen I know. was just using the pseudo way the OP was using. – DSC Jun 09 '19 at 17:09
@BirchPoirier literally the first comment under your question gives the answer away. – Aykhan Hagverdili Jun 09 '19 at 17:24
@Ayxan the OP assumed you needed to print a newline during his original `cout` which is wrong. You need to have a separate one in the first loop. – DSC Jun 09 '19 at 17:25
@DSC Well, OP never asked where to put new line characters. – Aykhan Hagverdili Jun 09 '19 at 17:28
@Ayxan That's true. I just helped him by typing the actual code so there wouldn't be a discussion. Don't get why that's an issue – DSC Jun 09 '19 at 17:30
I was going to ask where to put the newline characters next, DSC simply beat me to the punch. – Birch Poirier Jun 09 '19 at 17:34

How do I print an array row-by-row in C++?

2 Answers2