CS111 Lab Arrays, continued

Instructor: Michael Gordon

Arrays in Functions

To write a function title with an array as a

parameter, use the array declaration

without the size.

Example: int func(int a[])

To call a function with an array as an

argument, just use the array name.

Example: int x = func(grades)

Where int grades[] was previously declared.

Functions, continued

Arrays are, by default, pass by reference.

If your function needs to perform actions

on the entire array, you will need to

specify the array size as a parameter.

Example: int sum(int arr[], int size)

Two Dimensional Arrays

A 2D array can be thought of in two ways:

A grid/table of rows and columns of data

An array of arrays

You can declare it as follows:

e.g: int arrayName[5][4];

Function call: func(arrayName)

Function title example:

func(int a[][4], int rows)

Visualization

The grid below shows the addresses/indexes of each cell of an array c[5][4];

c[0][0] c[0][1] c[0][2] c[0][3]

c[1][0] c[1][1] c[1][2] c[1][3]

c[2][0] c[2][1] c[2][2] c[2][3]

c[3][0] c[3][1] c[3][2] c[3][3]

c[4][0] c[4][1] c[4][2] c[4][3]

Visualization, pop quiz

What’s the value in c[0][0]?

What’s the value in c[2][2]?

What’s the value in c[3][4]?

90 100 85 99

40 50 30 45

77 68 81 65

85 89 91 93

70 65 66 71