2 Dimensional array: strange values?

[nueur]

Hey guys,

I'm new to C++ and am getting confused while trying to use a 2d array.

Here's my code:

int testArr[5][5] = {0};
//test values
testArr[0][0] = 1;
testArr[0][1] = 2;
testArr[1][0] = 3;
testArr[1][1] = 4;

for( i=0; i<=5; i++ )
{
	for ( j=0; j<=5; j++ )
	{
		std::cout << "testArr["<<i<<"]["<<j<<"] = " << testArr[i][j] << "\n";
	}
}

And the output:

testArr[0][0] = 1
testArr[0][1] = 2
testArr[0][2] = 0
testArr[0][3] = 0
testArr[0][4] = 0
testArr[0][5] = 3
testArr[1][0] = 3
testArr[1][1] = 4
testArr[1][2] = 0
testArr[1][3] = 0
testArr[1][4] = 0
testArr[1][5] = 0
testArr[2][0] = 0
testArr[2][1] = 0
testArr[2][2] = 0
testArr[2][3] = 0
testArr[2][4] = 0
testArr[2][5] = 0
testArr[3][0] = 0
testArr[3][1] = 0
testArr[3][2] = 0
testArr[3][3] = 0
testArr[3][4] = 0
testArr[3][5] = 0
testArr[4][0] = 0
testArr[4][1] = 0
testArr[4][2] = 0
testArr[4][3] = 0
testArr[4][4] = 0
testArr[4][5] = -858993460
testArr[5][0] = -858993460
testArr[5][1] = -472153350
testArr[5][2] = 1964804
testArr[5][3] = 17324809
testArr[5][4] = 1
testArr[5][5] = 3823368

My main problem is that when set a value for the last column on row 0, it applys that same value to the first column on row 1 (seen above as with value: 3).

My second problem, which only seemed to happen during this test?(maybe it happened before but I missed it) is the crazy values in the last row?

If anyone could shed any light on my problem, I'd really appreciate it!

Thank you for your time.

[TheIdeasMan]

You are overrunning the bounds of the array.

The idiom for doing something 5 times is :

for( i=0; i<5; i++ ){}// no less than equal

the for loop ends when the end condition becomes false.

The array values go from 0 to 4.

When you specify [0][5] this really [1][1] because arrays are stored in linear order.

Same at the end values starting with [5] are past the end of the array - the last one is [4][4].

HTH

[nueur]

Wow, I feel foolish now.

Tottally missed that. Thanks a lot for clearing that up IdeasMan.

[TheIdeasMan]

No worries - any time, just mark the thread as solved, and we will catch up with you next time - cheers.