Thread: converting int to arrays, more info

  1. #1
    Registered User deleeuw's Avatar
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    converting int to arrays, more info

    hey all,

    how do one convert an integer that a user has entered into a location is an existing 2-d array?

    For example:

    #include <iostream.h>
    #include <stdlib.h>
    #include <stdio.h>


    main(){

    int y;
    int grid[4][4]={{1,5,9,13},{2,6,10,14},{3,7,11,15},{4,
    8,12,16}};

    cin>>y;
    int u;
    int U;
    y=grid[u][U];
    if (y==grid[3][3]){
    cout<<"good";
    }
    else{
    cout<<"bad";
    }
    }
    When I run this, I get a windows error, even tho I get no compiler errors.


    The actual array represents basically a game board. The comptuer "moves" 1 up, or 1 down, or 1 diagonally, etc. Obviously, the movement is based on its current position, as denoted by the coordinates (i.e. array[x][y]).
    The problem arises when the computer makes an illegal move, such a 2 spaces across. To prevent that, I use an if/then statement, referring to the intended coordinates (array [x][y]), and subtracting from them the coordinated of the present position, which, of course, is itself based on previous movements, etc., etc., starting all the way back with array[0][0]--the computer starts at the top left corner.

    The problem is that the coordinates, or [x][y], change, depending on the position on the "board". So I would need to refer to array[x][y] as a variable, as opposed to array[3][3], which is always 16.

    I hope that's kinda clear (!)

    Thanks

    777

  2. #2
    and the hat of int overfl Salem's Avatar
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    > int u;
    Contains garbage

    > int U;
    Contains garbage

    > y=grid[u][U];
    Overwrites the value of y you've just input with some wild array reference, caused by indexing it with two garbage values.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.

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