CODEWITHSUNDEEP
carrays
Tuong Nguyen Minh
Tuong Nguyen Minh

Reputation: 153

How to check if there is an element inside a two-dimensional array at a specific index location?

I am having this problem writing a function that when the user input x,y (the coordinate or index of two dimensional array) it will return 0 if there is nothing or 1 otherwise.

Upvotes: 1

Views: 4142

Answers (3)

lsk
lsk

Reputation: 532

Others have answered the question on whether an element exists or not by checking for a sentinel value. These answers assume that the 2D array is already allocated. If your situation had a different mem allocation model (allocate 1D initially and allocate the 2D dynamically), then you would also have to check whether the 2D is actually allocated for any 1D index. 1D => first dimension; 2D => second dimension.

Upvotes: 0

Ran Eldan
Ran Eldan

Reputation: 1350

In order to do so, first thing you need to do is initializ the array. You can do it this way:

int i,j;
for (int i = 0; i<SizeX; i++) {
    for (int j = 0; j<SizeY; j++) {
        arr[i][j] = 0;
    }
}

Now you can easly check it this way:

int check (int arr[SizeX][SizeY] , int i , int j) {
    // out-of-bound check
    if (i < SizeX && j < SizeY) {
        return (arr[i][j] == NULL ? 0 : 1);
    }else {
        // -1 indicate error - out of bound indexes
        return (-1);
    }
}

Upvotes: 3

user2600366
user2600366

Reputation: 68

What do you mean by nothing?

If you dont initialize your arry, it contains garbage values,

but if you do, u can check whether the cell contains the original value or a diffrent

one, and then return 1 or 0.

Upvotes: 0

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