﻿ C++ Exercises: Convert a decimal number to octal number - w3resource

# C++ Exercises: Convert a decimal number to octal number

## C++ For Loop: Exercise-72 with Solution

Write a C++ program to convert a decimal number to an octal number.

Visual Presentation:

Sample Solution:-

C++ Code :

``````#include <iostream> // Include input/output stream library
#include <math.h>   // Include math library for mathematical functions
using namespace std; // Use the standard namespace

int main() // Main function where the execution of the program starts
{
int dec_num, rem, quot, i = 1, j; // Declare integer variables for decimal number, remainder, quotient, and loop counters
int oct_num[100]; // Declare an array to store octal digits, initialized to store up to 100 digits

cout << "\n\n Convert a decimal number to octal number:\n"; // Display message prompting for decimal to octal conversion
cout << "-----------------------------------------------\n"; // Display separator line
cout << " Input a decimal number: "; // Prompt user to input a decimal number
cin >> dec_num; // Read the decimal number input by the user

quot = dec_num; // Assign the value of dec_num to quot (initializing quotient with the decimal number)
while (quot != 0) // Loop to convert decimal number to octal
{
oct_num[i++] = quot % 8; // Store remainder (quotient modulo 8) as octal digit in the array
quot = quot / 8; // Calculate next quotient by dividing it by 8 (octal base)
}

cout << " The octal number is: "; // Display message indicating the octal number
for (j = i - 1; j > 0; j--) // Loop to print octal digits in reverse order
{
cout << oct_num[j]; // Output octal digits from the array in reverse order
}
cout << "\n"; // Move to the next line after printing the octal number
}
``````

Sample Output:

``` Convert a  decimal number to octal number:
-----------------------------------------------
Input a decimal number: 15
The octal number is: 17
```

Flowchart:

C++ Code Editor: