Matrix of chars

[Yume]

I have a problem who reads a matrix with nxm elements of strings and have to display the string which has the biggest length from each line.

Here's my code:

#include <iostream>
using namespace std;
int main ()
{
	char mat[100][100][100], t[100];
	int n, m, i, j, max=0;
	cout << "n= "; cin >> n;
	cout << "m= "; cin >> m;
	for (i=0; i<n; i++)
	{
		for (j=0; j<m; j++)
		{
			cout << "mat[" << i << "][" << j << "]= "; cin >> mat[i][j]; 
		}
	}
	for (i=0; i<n; i++)
	{
		for (j=0; j<m; j++)
		{
			if (max>strlen (mat[i][j]))
			{
				strcpy (max, strlen(mat[i][j]));
				strcpy (t, mat[i][j]);
			}
		cout << t << endl;
	}
	
}

The problem is that the compiler cannot compare two different types as you know (max>strlen (mat[i][j])) and i don't know how to change it. Any tip would be appriciated! Thank you!
By the way, i work in mingw.

[TheDestroyer]

Hey buddy,

just cast it!

if(max > static_cast<int>(strlen(mat[i][j]))
...

But I think this is not the problem. strlen works for NULL terminated characters, which means, your string has to end with NULL for strlen to work, here's an example:

char[100] mystr;
mystr[0] = 'g'
mystr[1] = 'j'
mystr[2] = 'e'
mystr[3] = 'a'
mystr[4] = 'y'

Now if you use strlen with this, you'll get a wrong answer. To get the right answer, you have to add this line too:

mystr[5] = NULL;

Your array doesn't differ conceptually whatsoever from an int array except that char's size is 1 byte. Can you ever measure the length of an array of ints? not really! So to do it, you have to terminate your string with a NULL like I mentioned. It's some kind of a special hack to make strings defined in size.

http://www.cplusplus.com/reference/clibrary/cstring/strlen/

Cheers :)

[vlad from moscow]

I think that you need not three dimensional matrix.

char mat[100][100][100], t[100];

[bbgst]

Since you're using c++, why don't you use std::string?

string mat[200][200];
// ...
if(mat[i][j].length() > max)
    max = mat[i]j[].length();

[Yume]

Thank you guys! I found the mistake now!