I picked A when the answer was B. In order to figure out this problem correctly I wrote out the 'mat' variable in a 4x4 grid on a piece of paper. The grid is passed into the "operation" method and if look at the two numbers passed in it is (1,2). These fill the variables r and c in the method signature. Walk through the loop multiplying the two numbers identified in the matrix [r][j] matrix [j] [c] to get the result. Each pass creates one of the numbers in the four number sequence result:
1 1 = 1
2 3 = 6
3 1 = 3
4 * 1 = 4
This gives the answer "b" {1,6,3,4}
9
I picked A when the answer was E. So the Math.random() returns a value between 0.0 and 1.0. Need to multiply by 6 to give value of 1-6. Multiply that *2 and that gives you a max of 12.
13
I picked C when answer was A. My oopisies is that I misread the line numbers[k] = numbers [k-1] + x to "k + 1"
22
I picked E when answer is A. In this case, the nested for loop iterate over numbers in column major order and 142536 would be printed
24
So I got this one completed wrong ˡᵒˡ. The reason that II and III can be added to the class without creating a compile time error is because they are new methods with new signatures. In the case of I that method it's really a change to an existing method so programs that use this class need to be recompiled.
Score:
8
I picked A when the answer was B. In order to figure out this problem correctly I wrote out the 'mat' variable in a 4x4 grid on a piece of paper. The grid is passed into the "operation" method and if look at the two numbers passed in it is (1,2). These fill the variables r and c in the method signature. Walk through the loop multiplying the two numbers identified in the matrix [r][j] matrix [j] [c] to get the result. Each pass creates one of the numbers in the four number sequence result: 1 1 = 1 2 3 = 6 3 1 = 3 4 * 1 = 4 This gives the answer "b" {1,6,3,4}
9
I picked A when the answer was E. So the Math.random() returns a value between 0.0 and 1.0. Need to multiply by 6 to give value of 1-6. Multiply that *2 and that gives you a max of 12.
13
I picked C when answer was A. My oopisies is that I misread the line numbers[k] = numbers [k-1] + x to "k + 1"
22
I picked E when answer is A. In this case, the nested for loop iterate over numbers in column major order and 142536 would be printed
24
So I got this one completed wrong ˡᵒˡ. The reason that II and III can be added to the class without creating a compile time error is because they are new methods with new signatures. In the case of I that method it's really a change to an existing method so programs that use this class need to be recompiled.