This document discusses arrays in C++. It defines an array as a collection of variables of the same type that is used to store data. The syntax for declaring a one-dimensional array is shown as dataType arrayName[arraySize]. A two-dimensional array can store elements in a table-like structure with rows and columns defined as data_type array_name[x][y]. Functions can accept arrays as arguments by passing just the array name. Examples are provided for storing user input in arrays, accessing elements, and calculating averages by passing an array to a function. Exercises are presented on using arrays to store and print odd/even numbers, calculate function values for stored inputs, and perform operations on two-dimensional arrays
3. What is a Array?
An array is used to store a collection of data, but it is often more useful to think of an
array as a collection of variables of the same type.
An array must be defined before it can be used to store information.
An array definition specifies a variabel type and a name.
6. Two-Dimensional Arrays
you can create an array of an array known as multi-dimensional array.
data_type array_name[x][y]; For example: int x[3][4];
Here, x is a two dimensional array. It can hold a maximum of 12 elements. You can think
this array as table with 3 rows and each row has 4 columns as shown below.
7. Two-Dimensional Arrays
#include <iostream>
using namespace std;
int main () {
// an array with 2 rows and 2 columns.
int a[2][2];
Int i,j;
// input each array element's value
for ( i = 0; i < 2; i++ )
for ( j = 0; j < 2; j++ ) {
cout << "a[" << i << "][" << j << "]: ";
cin>> a[i][j];
cout<< endl;
}
// output each array element's value
cout<< "PRINT" <<endl;
for ( i = 0; i < 2; i++ )
for ( j = 0; j < 2; j++ ) {
cout << "a[" << i << "][" << j << "]: ";
cout<<a[i][j]<< endl;
}
}
8. Passing Arrays to Functions
C program to pass an array containing age of person to a function. This function should
find average age and display the average age in main function.
#include <iostream>
#include <iomanip>
using namespace std;
float average(float age[]);
int main()
{
float avg, age[6];
cout<<"age:"<<endl;
for (int i=0;i<6;i++){
cin>>age[i];
}
avg = average(age); /* Only name of array is passed as
argument. */
cout<<"Average age="<<setprecision(2)<<avg;
}
float average(float age[])
{
int i;
float avg, sum = 0.0;
for (i = 0; i < 6; ++i) {
sum += age[i];
}
avg = (sum / 6);
return avg;
}
9. EXERCISES 1
Write a program that to store and print odd & even number entered
by the user (Storing 10 number entered by user in an array)
10. EXERCISES 2
Write a program using function and array that to store and print value of f(x) = x2+
3x + 1, then find the values. (Storing 5 number entered by user in an array)
11. EXERCISES 3
Write a program that calculates Two-Dimensional
Arrays (Add & Substract)