# C++ program to convert octal number to decimal number using class

Submitted by Shubh Pachori, on August 08, 2022

## Problem statement

Given an octal number, we have to convert it to decimal number using the class and object approach.

Example:

```Input:
Enter Octal Number: 43

Output:
Decimal Number: 35
```

## C++ code to convert octal number to decimal number using class and object approach

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

// create a class
class OctalToDecimal {
// private data member
private:
int octal;

// public functions
public:
// getOctal() function to get Octal Number
void getOctal() {
cout << "Enter Octal Number:";
cin >> octal;
}

// OToD() function to convert octal to decimal
int OToD() {
// initialising variables to perform operations
int decimal = 0, index = 0, remain;

// while loop to convert octal to decimal
while (octal) {
remain = octal % 10;
octal = octal / 10;
decimal = decimal + remain * pow(8, index);
index++;
}

// returning decimal number
return decimal;
}
};

int main() {
// create a object
OctalToDecimal O;

// initialize a int type variable to store the value
int d;

// calling getOctal() function to insert the Octal Number
O.getOctal();

// calling OToB() function to convert it
d = O.OToD();

cout << "Decimal Number:" << d;

return 0;
}
```

### Output

```Enter Octal Number:122
Decimal Number:82
```

### Explanation

In the above code, we have created a class OctalToDeimal, one int type data member octal to store the octal number, and public member functions getOctal() and OToD() to store and convert the given octal number to decimal number.

In the main() function, we are creating an object O of class OctalToBinary, reading the octal number given by the user using getOctal() function, and finally calling the OToD() member function to convert the given octal number. The OToD() function contains the logic to convert the given octal number to a decimal number and printing the result.