Lesson 5.13 · Trace it

Trace: column totals (Java)

Java code19 rows to fill3 marks

Complete the trace table for this Java code. grid has 3 rows of 2 values, and grid[r][c] is the value in row r, column c. The outer loop goes along the columns and the inner loop goes down the rows. Then answer the question below the table. [3]

Line 1: int[][] grid = {{4, 7}, {9, 3}, {6, 8}};1int[][] grid = {{4, 7}, {9, 3}, {6, 8}};
Line 2: for (int c = 0; c < grid[0].length; c++) {2for (int c = 0; c < grid[0].length; c++) {
Line 3, indented 1 level: int total = 0;3    int total = 0;
Line 4, indented 1 level: for (int r = 0; r < grid.length; r++) {4    for (int r = 0; r < grid.length; r++) {
Line 5, indented 2 levels: total = total + grid[r][c];5        total = total + grid[r][c];
Line 6, indented 1 level: }6    }
Line 7: }7}

Fill in one row each time a line changes c, r or total. The table already has the right number of rows. In each row, write only what that line changes; you can leave the other cells empty or copy their values down. Write values the way Java shows them: 3 and 3.0 are different, and text goes in quotes.

Row	c	r	total
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

How many times did the line total = total + grid[r][c]; run?