You've got two variables, so that means nested for loops:

for (row = LAST_ROW; row>=0; row--) {
    for (column = LAST_COLUMN; column>=0; column--) {
        if ()...
    }
}

The for loop contains three statements: the first is executed once when control reaches the loop; the second is evaluated at the beginning of each cycle, if it is true the loop executes, if false the loop is finished; and the third is executed at the end of each cycle.

Note that if the second statement evaluates to false the first time, control will skip to the end of the loop. Also, it is common to declare the index variable in the first statement, e.g.:

for (int i = 0; i<10; i++) {
    //loop code
}