Which of the following statements assigns the letter S to the third row and first column of a two-dimensional array named strGrid (assuming row-major order).
In row-major order the row is specified first followed by the column. Row and column indices start with 0. So letterGrid[2][0] is the 3rd row and 1st column.
int[][] matrix = { {1,1,2,2},{1,2,2,4},{1,2,3,4},{1,4,1,2}};
int sum = 0;
int col = matrix[0].length - 2;
for (int row = 0; row < 4; row++)
{
sum = sum + matrix[row][col];
}
Since col is matrix[0].length - 2 it is 4 - 2 which is 2. This code will loop through all the rows and add all the numbers in the third column (index is 2) which is 2 + 2 + 3 + 1 which is 8.
int [][] mat = new int [4][3];
for (int row = 0; row < mat.length; row++)
{
for (int col = 0; col < mat[0].length; col++)
{
if (row < col)
mat[row][col] = 1;
else if (row == col)
mat[row][col] = 2;
else
mat[row][col] = 3;
}
}
This woud be true if the code put a 3 in the array when the row index is less than the column index and a 2 in the array when the row and column index are the same, and a 1 in the array when the row index is greater than the column index.
This code will put a 1 in the array when the row index is less than the column index and a 2 in the array when the row and column index are the same, and a 3 in the array when the row index is greater than the column index.
The first if will change an odd number to an even. The second if will also execute after an odd number has been made even. Both loops start at index 1 so this only changes the items in the second row and second and third column.
A two-dimensional array, imagePixels, holds the brightness values for the pixels in an image. The brightness can range from 0 to 255. What does the following method compute?
public int findMax(int[][] imagePixels)
{
int r, c;
int i, iMax = 0;
for (r = 0; r < imagePixels.length; r++)
{
for (c = 0; c < imagePixels[0].length; c++)
{
i = imagePixels[r][c];
if (i > iMax)
iMax = i;
}
}
return iMax;
}
The maximum brightness value for all pixels in imagePixel
The method works by scanning all the pixels in imagePixels and comparing them to the current iMax value. If the current is greater, it replaces iMax and becomes the new maximum brightness. This is the value that is returned.
This could be accomplished by adding the brightness in the second loop and comparing the sum to iMax after the second loop finishes and before the first loop starts again.
To do this you would need a third loop and an array, 256 in size. In the second loop you would track how many pixels of a certain brightness had occurred using, countBright[i]++, and then in the third loop find the item in countBright with the highest value.
Firstly, you would need to traverse the 2D array in the opposite order, going through the rows instead of the columns. Then, you would sum each row’s brightness in the second loop and compare it to the max in the first loop.
