Chapter 7, Problem 10AW

Program Plan Intro

Two-dimensional array:

A two dimensional array is also called as a multi-dimensional array; a multidimensional array is that all the identical arrays are put together into a single array.

• This is useful for storing same type of multiple sets of data in same place.
• The main advantage is that one-dimensional array can hold only one set of value, whereas, two-dimensional array can hold multiple sets of data in the form of rows and columns.
• The structure of a multi-dimensional array is lookalike a table (that is combination of rows and columns); it contains same type of columns.
• The first size declarator in the two-dimensional array represents row and the second size declarator represents column.
• The two dimensional array can have multiple length fields, which holds the number of rows.
  • Each row in the two dimensional array has a length field which holds the number of columns.

Syntax:

The syntax of two dimensional arrays is as follows:

datatype array_name [number_of_rows][number_of_columns];

From the given syntax, a two-dimensional array named “grades” of type “int” has been created with 30 rows and 10 columns.

Explanation of Solution

b. Code to sum all the elements in a column of 2D array and store it in a variable:

//Class definition

public class Sample {

// define main function

public static void main(String[] args) {

// Creation of 2D array with size declarator

int[][] days = new int[29][5];

// Declaration of accumulator variable

int total;

// Loop to read through the values in the column

for (int col = 0; col < 5; col++) {

// Initialize the accumulator variable

total = 0;

// Loop to read through each row

for (