C++ Program For Octal To Decimal Conversion

In this article, we will discuss the C++ program for octal to decimal conversion with its explanation.

Program:

Here's a simple C++ program to convert an octal number to its decimal equivalent:

#include <iostream>
#include <cmath>
using namespace std;
int octalToDecimal(int octalNumber) {
int decimalNumber = 0, i = 0, remainder;
while (octalNumber != 0) {
remainder = octalNumber % 10;
decimalNumber += remainder * pow(8, i);
++i;
octalNumber /= 10;
}
return decimalNumber;
}
int main() {
int octalNumber;
cout << "Enter an octal number: ";
cin >> octalNumber;
int decimalNumber = octalToDecimal(octalNumber);
cout << "Decimal equivalent: " << decimalNumber << endl;
return 0;
}

Output:

C++ Program For Octal To Decimal Conversion

Explanation:

1. Include Header Files:

#include <iostream>
#include <cmath>

#include <iostream>: This line includes the header file for the input/output stream, which is required to operate on input and output.
#include <cmath>: This line includes the cmath header file, which is required to compute powers with the pow function.

2. namespace:

As this line declares, the program will use the std namespace. The standard C++ library is contained in the std namespace.

3. Function for Octal to Decimal Conversion:

int octalToDecimal(int octalNumber) {
int decimalNumber = 0, i = 0, remainder;
while (octalNumber != 0) {
remainder = octalNumber % 10;
decimalNumber += remainder * pow(8, i);
++i;
octalNumber /= 10;
}
return decimalNumber;
}

An octal number is passed to the octalToDecimal function, which returns its decimal equivalent.
It iterates through each digit of the octal number using a while loop.
The modulo operator (%) is used inside the loop to calculate the remaining digit.
The decimal equivalent is updated by multiplying the remainder by 8, raised to the power of i (the digit's position).
Until the octal number drops to zero, the loop is repeated.

4. Main Function:

int main() {
int octalNumber;
cout << "Enter an octal number: ";
cin >> octalNumber;
int decimalNumber = octalToDecimal(octalNumber);
cout << "Decimal equivalent: " << decimalNumber << endl;
return 0;
}

The program's entry point serves as the primary function.
It declares a variable called octalNumber to store the octal number the user enters.
Using cout and cin, the user is asked to enter an octal number.
The user-inputted octal number is passed as an argument to the octalToDecimal function, and the outcome is saved in the decimalNumber
After that, the user is shown the decimal equivalent via cout.