C Program For Octal to Decimal Conversion

// C program to demonstrate conversion of
// octal to decimal using format specifier
#include <stdio.h>

// Driver code
int main()
{
    int n;
    printf("Enter an Octal number: \n");
    scanf("%o", &n);
  
    // printing the result
    printf("\nDecimal Representation is: %d", n);
    return 0;
}

// C program to demonstrate conversion of
// octal to decimal without using pow()
#include <stdio.h>

// Function to convert octal to decimal
int octalToDecimal(int n)
{
    int decimalvalue = 0;

    // Assigning base value to 1, i.e 8^0
    int base = 1;

    int temp = n;
  
    // while loop executes the statements until the
    // condition is false
    while (temp) 
    {
        // Finding the last digit
        int lastdigit = temp % 10;
        temp = temp / 10;

        // Multiplying last digit with appropriate
        // base value and adding it to decimalvalue
        decimalvalue += lastdigit * base;

        base = base * 8;
    }

    return decimalvalue;
}

// Driver code
int main()
{
    int octalnum = 123;

    printf("decimal number is %d",
           octalToDecimal(octalnum));
}

// C program to demonstrate conversion of
// octal to decimal using pow()
#include <math.h>
#include <stdio.h>

int Octaltodecimal(int octal)
{
    int decimalnumber = 0, i = 0;

    // while loop executes the statements 
    // until the condition is false
    while (octal != 0) 
    {
        // Calculating equivalent decimal number 
        // for the given octal number
        decimalnumber = decimalnumber + 
                        (octal % 10) * pow(8, i++);
        octal = octal / 10;
    }
    // printing the result
    return decimalnumber;
}
// Driver code
int main()
{
    int octalnumber = 123;
  
    // calling function
    printf("decimal number is %d",
           Octaltodecimal(octalnumber));
    return 0;
}

// C program to demonstrate conversion of
// octal to decimal without using functions
#include <math.h>
#include <stdio.h>

// Driver code
int main()
{
    int octalnumber = 123, decimalnumber = 0;
    int i = 0;
  
    // while loop executes the statements 
    // until the condition is false
    while (octalnumber != 0) 
    {      
        // Calculating equivalent decimal number 
        // for the given octal number
        decimalnumber = decimalnumber
                        + (octalnumber % 10) * pow(8, i++);
        octalnumber = octalnumber / 10;
    }
  
    // Printing the result
    printf("decimal number is: %d", decimalnumber);
    return 0;
}