Why is this j considered an undeclared identifier when it's declared-CodePudding

The j in the printing statement is considered an undeclared identifier, how do I fix this?

for (int i = 0; i < 9; i  ) {
    for (int j = 0; j < 9; j  )
        switch(grid[i][j]){
            case '.':
                colourChange(WHITE);
                break;
            case 'P':
                colourChange(YELLOW);
                break;
            case 'G':
                colourChange(PINK);
                break;
            case 'W':
                colourChange(BLUE);
                break;}
        printf("%c  ", grid[i][j]);
    printf("\n");
}

I declared it in the for loop, but it gave an error. Also if I comment out the full switch statement it works.

CodePudding user response：

The body of the inner for loop is just the switch statement, so the call to printf that follows is outside of the inner loop.

Always use braces:

for (int i = 0; i < 9; i  ) {
    for (int j = 0; j < 9; j  ) {
        switch(grid[i][j]) {
            case '.':
                colourChange(WHITE);
                break;
            case 'P':
                colourChange(YELLOW);
                break;
            case 'G':
                colourChange(PINK);
                break;
            case 'W':
                colourChange(BLUE);
                break;
        }
        printf("%c  ", grid[i][j]);
    }
    printf("\n");
}

CodePudding user response：

This is because your second for statement. Since it has no curly braces, it assumes the next statement corresponds to its body. Your following printf("%c ", grid[i][j]); assumes that there is no j to take into account and is not recognized. A fixed solution may be:

for (int i = 0; i < 9; i  ) {
    for (int j = 0; j < 9; j  ) {
        switch(grid[i][j]) {
            case '.':
                colourChange(WHITE);
                break;
            case 'P':
                colourChange(YELLOW);
                break;
            case 'G':
                colourChange(PINK);
                break;
            case 'W':
                colourChange(BLUE);
                break;
        }
        printf("%c  ", grid[i][j]);
    }
    printf("\n");
}