LECTURE 11: Arrays (Read Sections *.1-8.3, 8.4)

So far, we covered simple data types (int, double, char) that

• use a single memory location to store a single variable

Often, we would like to group similar data items together. For example, we want to store and process exam scores of all students in the class. Arrays address this requirement!

Array is a collection of two or more adjacent memory locations, called array elements

Array declaration and use

double x[2]; // reserves two memory locations to store two double values

x[0] = 5.0; // assigns value 5.0 to the first element of the array

x[1] = 3.0;

printf(“%f”,x[0]); // prints out the value of the first element

x[1] = x[0] + x[1]; // updates the value of the second array element to 8.0

Array initialization

int sum = 0; // initialization of integer variable

double x[2] = {5.0, 3.0}; // initialize values of the two array elements

Array subscripts

double x[100];

x[0] = 5.0;

x[1] = 3.0;

for (i=3; i<=100; i=i+1)

x[i] = x[i-1] + x[i-2];

Question: what will be the value of element x[99] after the for loop is executed?

Example: Enter exam scores and find maximum and average scores

- DONE IN CLASS –

- YOU CAN ALSO CHECK 8.6 IN THE TEXTBOOK –

Miltidimensional Arrays

char tictactoe[3][3]; // declares two-dimensional array with 3 rows and 3 columns

tictactoe[0][2] = ‘x’; // assigns value ‘x’ to the element in the

// first row and third column of tictactoe