# C++ program to find the sum of prime numbers in a range using class

Submitted by Shubh Pachori, on September 01, 2022

## Problem statement

Given a range, we have to find the sum of prime numbers in that range using class and object approach.

Example:

```Input:
Enter Range: 1 9

Output:
Prime Numbers in the range 1 to 9 are 1 2 3 5 7
Sum of prime numbers in range is 18
```

## C++ code to find the sum of prime numbers in a range using the class and object approach

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

// create a class
class Prime {
// declare private data members
private:
int start, end;

// public functions
public:
// getRange() function to insert range
void getRange() {
cout << "Enter Range: ";
cin >> start >> end;
}

// sumPrime() function to print prime numbers in between range
int sumPrime() {
// initilaize int type variables to perform operations
int index_1, index_2, sum = 0, check = 1;

cout << "Prime Numbers in the range " << start << " to " << end << " are ";

// for loop to search prime number in the range
for (index_1 = start; index_1 <= end; index_1++) {
// counter variable
int check = 0;

// for loop for checking if the number is prime or not
for (index_2 = 2; index_2 < index_1; index_2++) {
// if condition to check if the index_1
// is divisible by the index_2
if (index_1 % index_2 == 0) {
// counter increased by 1
check++;

// break statement to break the loop
break;
}
}

// if the counter is zero then the index_1 number
// is printed and added to the sum
if (check == 0) {
cout << index_1 << " ";

sum = sum + index_1;
}
}

// returning sum
return sum;
}
};

int main() {
// create an object
Prime P;

// int type variable to store
// sum of prime numbers
int sum;

// calling getRange() function
// to insert range
P.getRange();

// sumPrime() function to add prime numbers
// in the range
sum = P.sumPrime();

cout << "\nSum of prime numbers in range is " << sum;

return 0;
}
```

### Output

```RUN 1:
Enter Range: 2 11
Prime Numbers in the range 2 to 11 are 2 3 5 7 11
Sum of prime numbers in range is 28

RUN 2:
Enter Range: 1 100
Prime Numbers in the range 1 to 100 are 1 2 3 5 7 11 13 17 19 23 29 31 37 41
43 47 53 59 61 67 71 73 79 83 89 97
Sum of prime numbers in range is 1061
```

### Explanation

In the above code, we have created a class Prime, two int type data members start and end to store the start and end of the range, and public member functions getRange() and sumPrime() to store range and to print sum of the prime numbers in between that given range.

In the main() function, we are creating an object P of class Prime, reading a range by the user using getRange() function, and finally calling the sumPrime() member function to print the sum of prime numbers in the given range. The sumPrime() function contains the logic to print the sum of prime numbers in the given range and printing the result.