# C++ Program to Calculate average of n numbers using arrays

January 21, 2023, Learn eTutorial
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In this C++ program, we are calculating the average of n numbers, where, n is specified by the user using arrays

## How to calculate the average of numbers?

Average is the arithmetic mean and is calculated by adding a group of numbers and then dividing by the count. For example, the average of 20, 30, 30, 50, 70, and 100 is 300 divided by 6, which is 50.

## How to calculate the average of numbers using arrays in a C++ program?

First, the user is asked to enter a value of n. The value of n should be in the range of 1 – 100. If the value entered for n is not within the range, a `while loop` is executed to ask the user to enter a valid value for n. Now for a valid n, the user is asked to enter the n elements. These elements are stored in an array using a loop.

In C++, an array is a data type that can store multiple values of the same type. Here our array is float num[100]. Initially, we set a variable sum to 0. With in the `for loop`, every time a number is entered by the user, its value is added to the variable sum. By the end of the loop, the sum of all the n elements can be get from the variable sum. Then the average can be calculated by dividing the total sum by n.
avg = sum / n; Display the average on the screen.

### Algorithm

Step 1:  Call the header file` iostream.`

Step 2: Use the` namespace std`.

Step 3: Open the integer type main function; `int main().`

Step 4: Declare integer type variables n , i,  and float type array  num[100], sum=0.0, avg;

Step 5: Ask the user to enter the number of elements ( 1 to 100 ).

Step 6: read the number into the variable n;

Step 7: Check whether the entered value for n is in between the range 1 – 100.

Step 8: If the condition is not satisfied then print an error message and ask the user to enter a value within the range of 1 – 100;

Step 9: Ask the user to enter the numbers.

Step 10: Read the numbers into the array num[100].

Step 11: Calculate the sum of the n numbers and store it in the variable sum.

Step 12: Compute the average by avg = sum / n;

Step 13: Display avg;

Step 14: Exit;

## C++ Source Code

```                                          ```#include <iostream>
using namespace std;

int main()
{
int n, i;
float num[100], sum=0.0, avg;

cout << "Enter the numbers of data: ";
cin >> n;

while (n > 100 || n <= 0)
{
cout << "Error! number should in range of (1 to 100)." << endl;
cout << "Enter the number again: ";
cin >> n;
}

for(i = 0; i < n; ++i)
{
cout << i + 1 << ". Enter number: ";
cin >> num[i];
sum += num[i];
}

avg = sum / n;
cout << "Average = " << avg;

return 0;
}```
```

## OUTPUT

```Enter the numbers of data: 5
1. Enter number: 12
2. Enter number: 4
3. Enter number: 5
4. Enter number: 54
5. Enter number: 21
Average = 19.2```

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