Program for octal to decimal conversion in C++

Given with an octal number as an input, the task is to convert the given octal number into a decimal number.

Decimal numbers in computer is represented with base 10 and octal number is represented with base 8 starting from the digit 0 till 7 whereas decimal numbers can be any numeric digit starting from 0 – 9.

To convert an octal number into a decimal number follow these steps −

• We will extract digits starting from right to left through a remainder and then multiply it with the power starting from 0 and will be increased by 1 till the (number of digits) – 1
• Since we need to do conversions from octal to binary the base of power will be 8 as octal have base 8.
• Multiply the digits of given inputs with base and power and store the results
• Add all the multiplied values to obtain the final result which will be a decimal number.

Given below is the pictorial representation of converting an octal number into a decimal number.

Example

Input-: 451    1 will be converted to a decimal number by -: 1 X 8^0 = 1    5 will be converted to a decimal number by -: 5 X 8^1 = 40    4 will be converted to a decimal number by -: 4 X 8^2 = 256 Output-: total = 0 + 40 + 256 = 10

Algorithm

Start Step 1-> declare function to convert octal to decimal    int convert(int num)       set int temp = num       set int val = 0       set int base = 1       Set int count = temp       Loop While (count)          Set int digit = count % 10          Set count = count / 10          Set val += digit * base          Set base = base * 8       End       return val step 2-> In main()    set int num = 45    Call convert(num) Stop

Example

 Live Demo

#include <iostream> using namespace std; //convert octal to decimal int convert(int num) {    int temp = num;    int val = 0;    int base = 1;    int count = temp;    while (count) {       int digit = count % 10;       count = count / 10;       val += digit * base;       base = base * 8;    }    return val; } int main() {    int num = 45;    cout <<"after conversion value is "<<convert(num); }

Output

IF WE RUN THE ABOVE CODE IT WILL GENERATE FOLLOWING OUTPUT

after conversion value is 37