2D array scanf with function

Question

I want when I reserve or cancel, the number change, but it doesn't change. Im confused.. please help :!!

print seat code :

  int print_seats(void) {
        int i, j;

        printf("  |0  1  2  3  4\n");
        printf("  ---------------\n");

        for (i = 0; i < 3; i++)
        {
            printf("%d|", i);
            for (j = 0; j < 5; j++)
            {

it doesnt print 0:

            printf("%2d ", s[i][j]);
        }
        printf("\n");   
    }
    printf("\n");
}

reserve code :

int researve(int s[3][5]) {
    int row = 0, col = 0;

    printf("선택된 메뉴=예약하기\n\n");
    printf("예약을 원하는 자리는?(행 열) :");
    scanf("%d %d", &row, &col);

succed :

if (s[row][col] == 0)
        {           
            printf("예약이 완료되었습니다\n\n");
            s[row][col] = 1;
        }

fail : else { printf("예약이 완료되었습니다\n\n"); } return s[3][5]; }

main code :

int main(void) {
    int s[3][5] = {{ 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 }, { 0, 0, 0, 0, 0 }
    };

selecting menu :

            printf("선택된 메뉴=좌석 확인하기\n\n");
            print_seats();
            researve(s[3][5]);
            print_seats();

    return 0;
}

Note that return s[3][5]; at the end of function int researve(int s[3][5]) will access an out of range (non-existent) array element. — Weather Vane
– Weather Vane, Commented May 19, 2020 at 14:04

Lou Franco · Accepted Answer · 2020-05-19 14:08:25Z

1

I think you just want to remove this line:

s[i][j]=0;

in print_seats. At the beginning of your program, it's already 0.

A function that prints an argument should usually not change it.

You are already updating this to 1 in reserve, but you revert that change every time you print.

Also, as @WeatherVane mentioned in a comment, the return s[3][5] is never a valid int. You probably should make this void and not return anything, but returning s[row][col] would be ok.

I should also mention that you should check that row/col are within range of your array before using them as indexes.

edited May 19, 2020 at 14:08

answered May 19, 2020 at 14:02

Lou Franco

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3 Comments

Eby Over a year ago

if i remove that line its execute a weird number

Lou Franco Over a year ago

You should pass s from main to the function

Lou Franco Over a year ago

It looks like you might have another (global) s. The one in main is initialized to 0. But it looks like you aren’t using it in print_seats

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