3. OBJECTIVES
At the end of this module, students should be
able to:
Declare and use an array
Use the array statement in C++ program
Accessing element in an array
4. ARRAY DEFINITION
Array is a collection of data elements of the
same type that are referenced by a common
name.
Used to process a collection of data all of which is
of the same type, such as list of name, list of
temperature.
5. ARRAY DEFINITION
Array’s element consist of memory allocation and
identified by index.
Array size : 9
1st Index Indexs
0 1 2 3 4 5 6 7 8
6. Two types of arrays
One-dimensional array
Two-dimensional array
7. DECLARING ONE DIMENSIONAL
ARRAY
Will have a single row and can have any number
of columns.
Will have only one subscript. Subscript refers to
the dimension of the array.
Array declaration of 10 alphabet
type array_name[size]
Eg : char huruf[10];
8. INITIALIZING ONE DIMENSIONAL
ARRAY
Initialization is the process of assigning values to
the array you have created.
To assign initial values to each one of array’s
elements we must enclose the values in curly
braces ({ }) and separate them with comma (,).
Eg : char huruf[5] = {‘a’, ‘b’, ‘c’, ‘d’, ‘e’};
9. INITIALIZING ONE DIMENSIONAL
ARRAY
Eg: int nombor[3] = {3, 24, 31};
first index 0 1 2
nombor 3 24 31
nombor[0];//3
nombor[1];//24
nombor[2];//31
nombor[0+1];//nombor[1];//24
nombor[3];
10. ACCESSING ELEMENT OF ONE
DIMENSIONAL ARRAY
Element is accessed by its index
Array index refers to the location of the values in an
array.
The first element will always have the array index as
0.
Syntax :
<Variable name>[Array index] = Value;
For example:
marks[0]=95;
marks[1]=85;
marks[2]=75;
11. ACCESSING ELEMENT OF ONE
DIMENSIONAL ARRAY
Eg:
int my_array[5] = {11, 22, 33, 44, 55};
to store the value 75 in the third element
of my_array, we could write the following
statement:
my_array[2] = 75;
to pass the value in 4th element of my_array and
store the value into temporary variable,
temp_value:
int temp_value = my_array[3]; // also
equals to 44
12. ACCESSING ELEMENT OF ONE
DIMENSIONAL ARRAY
if the name of an array is name, then name[0] is
the name of the element that is in position 0,
name[1] is the name of the element that is in
position 1, etc.
in general, the nth element is in position n-1. So
if the array has n elements, their names are
name[0], name[1], name[2], …, name[n-
1].
it is important to be able to clearly distinguish
between the two uses that brackets [ ] have
related to arrays:
int name[5]; // declaration of a new array
name[2] = 75; // access to an element of the
array.
13. EXAMPLE
Program Student_Marks.cpp will illustrate how
to declare an array, initialize and access its
elements.
19. ENTERING DATA INTO AN ARRAY
When more number of values are to be stored
in an array, a for loop can be used.
The sample code shows how to use a for loop
in an array.
for(int i=0;i<5;i++)
{
cout<<“Enter the marks: ";
cin>>marks[i];
}
20. READING DATA FROM AN ARRAY
You can use a for loop with a single cout
statement to print the values from an array.
for (int i=0;i<5;i++)
{
cout<<"Marks : "+marks[i]);
}
21. EXAMPLE
Program One_Int_Array.cpp illustrates how to
accept five marks from the user and prints the
values on the screen.
22. #include <iostream>
using namespace std;
void main()
{
int marks[5];
//Accepting the marks
for(int i=0;i<5;i++){
cout<<"Enter mark :";
cin>>marks[i];
}
cout<<"nThe marks you have enter is"<<endl;
//Displaying the array
for(int i=0;i<5;i++){
cout<<"Marks:"<<marks[i]<<endl;
}
}
23.
24. IN CLASS EXERCISE 4.1
Declare an array alpha of 15 elements of type
int.
Access the value of tenth element of array alpha.
Set the value of fifth element of array alpha to
35.
Set the value of ninth element of array alpha to
the sum of fifth and sixth element of array
alpha.
25. Declare an array alpha of 15 elements of type
int.
int alpha [15];
Access the value of tenth element of array alpha.
alpha [9];
Set the value of fifth element of array alpha to
35.
alpha [4] = 35;
26. Set the value of ninth element of array alpha to
the sum of fifth and sixth element of array
alpha.
alpha [8] = alpha [4] + alpha [5]
27. What is the output
#include<iostream>
using namespace std;
void main()
{
double num []= {2.0, 4.0, 6.5, 8.7};
cout<<num[1+2];
}
28. How to fill in value into array Output:
//program output
#include <iostream> 1
using namespace std; 2
void main() 3
{ 4
for(int i = 0; i < 10; ++i) 5
{ 6
cout << i+1 << “n";
7
}
8
}
9
10
29. #include <iostream>
using namespace std;
void main()
{
int num[]={1,2,3,4,5,6,7,8,9,10};
for(int i = 0; i < 10; ++i)
{
cout << num[i]<< "n";
}
}
30. TWO-DIMENSIONAL ARRAY
Two-dimensional arrays can be described as
"arrays of arrays".
For example, a two-dimensional array can be
imagined as a two-dimensional table made of
elements of a same uniform data type.
32. Assume that there are 5 students in a class and
each of them study three different subjects, for
example Mathematics, Physics and Chemistry.
33. Example
int marks_table [5][3];
Syntax
<Data type> <Variable name> [Row][Column];
34. TWO-DIMENSIONAL ARRAY
Table jimmy represents a bidimensional array of
3 by 5 elements of type int.
The way to declare this array in C++ would be:
int jimmy [3][5];
column
row
36. ACCESSING ELEMENT IN TWO-
DIMENSIONAL ARRAY
Element is accessed by the index of its row and
column.
Eg:
Toaccess the element in the 2nd row and at the 4th
column of this two-dimentional array, we can used
the following code:
jimmy[1][3];
39. WHAT IS OUTPUT?
#include<iostream>
using namespace std;
void main()
{
int marks_table[5][3] = {{83,99,74},
{88,90,72},{89,88,82},
{98,93,75},{78,60,65}};
cout<<marks_table[1][2];
}
40.
41. #include<iostream>
#include<string>
using namespace std;
void main()
{
string Data [2][3];
//For first fow
Data[0][0] = "Lisa"; //lastname
Data[0][1] = "Sulaiman"; //firstname
Data[0][2] = "Kedah"; //location
//Second row
Data[1][0] = "Ali"; //lastname
Data[1][1] = "Muhammad"; //firstname
Data[1][2] = "Johor"; //location
cout<<"LastnametFirstnametLocationn";
for(int i=0;i<2;i++){
for(int j=0;j<3;j++){
cout<<Data[i][j]<<"tt";
}
cout<<"n";//move to new line
}
}
42. #include <iostream>
using namespace std;
void main()
{
int array2[ 23 ][ 4 ];
//Accepting the marks
for (int row=0; row<2; row++) {
for(int col=0; col<3; col++){
cout<<"Enter mark ["<<(row)<<"][" <<col <<"]: ";
cin>>array2[row][col];
}
cout<<endl;
}
//display
for(int row=0; row<2; row++){
for(int col=0; col<3; col++)
cout<<array2[row][col] << " ";
cout<<endl;
}
}
44. IN CLASS EXERCISE 4.2
Declare an array beta of 10 rows and 20 columns
of type int.
Examine the following:
double values[ ] [ ] = {
{1.2, 9.0, 3.2},
{9.2, 0.5, 1.5},
{7.3, 7.9, 4.8} } ;
What is the value of values[2][1]?
45. Which of the following statements constructs
an array with 5 rows of 7 columns?
long stuff[5][7];
long[5][7];
long stuff[7][5];
long [7][5];
46. Declare an array beta of 10 rows and 20 columns
of type int.
int beta [10][20]
o Value of values[2][1]? 7.9
o long stuff[5][7];
47. SUMMARY
An array is a structured data type with a fixed
number of elements.
Every element of an array is of the same type
and can be accessed by their index.
Array index started with 0.
Array can be initialized during declaration.
A one-dimensional array has one subscript.
In two-dimensional array, elements are arranged
in table form.
To access element from two-dimensional array,
pair of indices is needed (index for row and index
for column).
