2D Arrays

Name: ____________________________________________________ Alpha: _____________ Section: ________

Describe help received: _________________________________________________________________

See the bottom for how to submit your work.

Due: Before 0800 on next class day

(10 pts) Read today's lecture notes. Honestly declare how you read the notes.
1. (10 pts) I read the notes carefully. I have a good understanding of the topics therein.
2. (10 pts) I read the notes carefully, but I don't really understand the following points well:
3. (0 pts) I didn't read the notes carefully.

[10pts] Complete the code below that creates a variable A and allocates and initializes so that we have the situation depicted in the picture.



int** A;

A =                                ;

for (           ;              ;             ) 
{

  A[  ] =                    ; 

  for(              ;              ;                )
  {
      A[i][j] =                            ;
  }
}

[80pts] Write a program hw.cpp that works as follows:

~/$ ./hw
What size? 2 x 3 
1 8 0
4 7 7 
rows: 0 1 
cols: 1

In particular:

The program asks the user to specify a size n x m of a matrix of integers.
It reads in n x m numbers.
It prints out the indices of rows and columns such that the sum of numbers in that row or column is a multiple of 3.

For the above run,

Row 0 has 1, 8, and 0. The sum is 9, which is a multiple of 3!
Row 1 has 4, 7, and 7. The sum is 18, which is also a multiple of 3!

Therefore, both of rows 0 and 1 are listed in the output.

Column 0 has 1 and 4. The sum is 5, which is not a multiple of 3.
Column 1 has 8 and 7. The sum is 15, which is a multiple of 3!
Column 2 has 0 and 7. The sum is 7, which is not a multiple of 3.

Therefore, only column 1 is listed in the output.

Here are some more example runs. Your program must read input and produce output with the exact same formatting! The red text represents the user input.

~/$ ./hw
What size? 1 x 1
6
rows: 0 
cols: 0

~/$ ./hw
What size? 1 x 1
5
rows:
cols:

~/$ ./hw
What size? 3 x 3 
6 9 5
4 6 8
9 4 14
rows: 1 2 
cols: 2

~/$ ./hw
What size? 5 x 3
3 4 1 
6 2 3
2 4 5
1 3 2
3 2 4
rows: 3 4 
cols: 0 1 2

~/$ ./hw
What size? 3 x 5
3 6 2 1 3 
4 2 4 3 2 
1 3 5 2 4 
rows: 0 1 2 
cols: 3 4

Submit to the submission server (due: 0800 on the next class day)

~/bin/submit -c=IC210 -p=hw23 hw.cpp

Bring to class

A printout of this homework sheet annotated with your answers
The codeprint of hw.cpp.