C - Part 43

C Program To Convert Decimal To Octal Number In One Line

Lets write a C program to convert a number from Decimal number system(base 10) to Octal number system(base 8) in one line.

Expected Output for the Input

User Input:
Enter a Decimal Number
90

Output:
Octal representation of Decimal number 90 is 132

Logic To Convert Decimal To Octal Number In One Line of Code

In c programming language, any decimal number you store will also be stored in Octal form and you can print it using %o format specifier.

Video Tutorial: C Program To Convert Decimal To Octal Number In One Line

[youtube https://www.youtube.com/watch?v=41-xLNYbvDY]

YouTube Link: https://www.youtube.com/watch?v=41-xLNYbvDY [Watch the Video In Full Screen.]

Source Code: C Program To Convert Decimal To Octal Number In One Line

#include < stdio.h >

int main()
{
    int num;

    printf("Enter a Decimal Number\n");
    scanf("%d", &num);

    printf("\nOctal representation of Decimal number %d is %o\n", num, num);

    return 0;
}

Output 1:
Enter a Decimal Number
16

Octal representation of Decimal number 16 is 20

Output 2:
Enter a Decimal Number
41

Octal representation of Decimal number 41 is 51

Output 3:
Enter a Decimal Number
90

Octal representation of Decimal number 90 is 132

Output 4:
Enter a Decimal Number
14

Octal representation of Decimal number 14 is 16

Output 5:
Enter a Decimal Number
32

Octal representation of Decimal number 32 is 40

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

C Program To Convert Octal Number To Decimal Number, using While Loop

Lets write a C program to convert a number from Octal number system(base 8) to Decimal number system(base 10), using while loop.

Number Systems

number systems

1. Binary Number System uses base 2 and digits 01.
2. Octal Number System uses base 8 and digits 01234567.
3. Decimal Number System uses base 10 and digits 0123456789.
4. Hexadecimal Number System uses base 16 and digits 0123456789ABCDEF.

Note: Octal number system can be derived by base 8 to the power of whole numbers.

Example:
etc .. 8⁴, 8³, 8², 8¹, 8⁰

etc .. 8⁴ = ‭4,096‬, 8³ = 512, 8² = 64, 8¹ = 8, 8⁰ = 1.

octal number system

Expected Output for the Input

User Input:
Enter an Octal Number
24

Output:
Decimal Equivalent of 24 is 20.

Explanation:

Decimal to binary

If user enters num = 24.

(8³ x 0) + (8² x 0) + (8¹ x 2) + (8⁰ x 4 )
= 0 + 0 + (8 x 2) + (1 x 4)
= 16 + 4
= 20
So Decimal equivalent of Octal number 24 is 20.

Video Tutorial: C Program To Convert Octal Number To Decimal Number, using While Loop

[youtube https://www.youtube.com/watch?v=QVksCjl2yhY]

YouTube Link: https://www.youtube.com/watch?v=QVksCjl2yhY [Watch the Video In Full Screen.]

Logic To Convert Octal Number To Decimal Number, using While Loop

In this C program we ask the user to enter / input an Octal number. Using while loop we calculate the reminder and add it to previous value of variable dec, along with pow(8, place). We make use of variable place to position the reminder.
dec = dec + rem * pow(8, place);

octal number system

Source Code: C Program To Convert Octal Number To Decimal Number, using While Loop

#include < stdio.h >
#include < math.h >

int main()
{
    int num, dec = 0, rem = 0, place = 0;

    printf("Enter an Octal Number\n");
    scanf("%d", &num);

    printf("\nDecimal Equivalent of %d is ", num);
    while(num)
    {
        rem = num % 10;
        dec = dec + rem * pow(8, place);
        num = num / 10;
        place++;
    }
    printf("%d\n", dec);

    return 0;
}

Output 1:
Enter a decimal number
16

Octal Equivalent of 16 is 20

Output 2:
Enter an Octal Number
24

Decimal Equivalent of 24 is 20

Output 3:
Enter an Octal Number
132

Decimal Equivalent of 132 is 90

Output 4:
Enter an Octal Number
16

Decimal Equivalent of 16 is 14

Output 5:
Enter an Octal Number
40

Decimal Equivalent of 40 is 32

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

C Program To Convert Decimal Number To Octal Number, using While Loop

Lets write a C program to convert a number from Decimal number system(base 10) to Octal number system(base 8), using while loop.

Number Systems

number systems

Note: Octal number system can be derived by base 8 to the power of whole numbers.

Example:
etc .. 8⁴, 8³, 8², 8¹, 8⁰

etc .. 8⁴ = ‭4,096‬, 8³ = 512, 8² = 64, 8¹ = 8, 8⁰ = 1.

octal number system

Expected Output for the Input

User Input:
Enter a decimal number
20

Output:
Octal equivalent of 20 is 24.

Explanation:
If user enters num = 20

We keep on dividing the number 20 by 8.

20 / 8 = 2, reminder 4.
02 / 8 = 0, reminder 2.

Decimal to binary

So Octal equivalent of decimal number 20 is 24.

(8³ x 0) + (8² x 0) + (8¹ x 2) + (8⁰ x 4 )
= 0 + 0 + (8 x 2) + (1 x 4)
= 16 + 4
= 20

Video Tutorial: C Program To Convert Decimal Number To Octal Number, using While Loop

[youtube https://www.youtube.com/watch?v=zd_rO67U-Gw]

YouTube Link: https://www.youtube.com/watch?v=zd_rO67U-Gw [Watch the Video In Full Screen.]

Logic To Convert Decimal Number To Octal Number, using While Loop

In this C program we ask the user to enter / input a decimal number. Using while loop we calculate the reminder and add it to previous value of variable oct. We make use of variable place to position the reminder based on number system – unit, ten, hundred, thousand, ten thousand etc.

Source Code: C Program To Convert Decimal Number To Octal Number, using While Loop

#include < stdio.h >

int main()
{
    int num, oct = 0, rem = 0, place = 1;

    printf("Enter a decimal number\n");
    scanf("%d", &num);

    printf("\nOctal Equivalent of %d is ", num);
    while(num)
    {
        rem = num % 8;
        oct = oct + rem * place;
        num = num / 8;
        place = place * 10;
    }
    printf("%d\n", oct);

    return 0;
}

Output 1:
Enter a decimal number
16

Octal Equivalent of 16 is 20

Output 2:
Enter a decimal number
41

Octal Equivalent of 41 is 51

Output 3:
Enter a decimal number
90

Octal Equivalent of 90 is 132

Output 4:
Enter a decimal number
14

Octal Equivalent of 14 is 16

Output 5:
Enter a decimal number
32

Octal Equivalent of 32 is 40

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

C Program To Convert Binary Number To Decimal Number, using While Loop

Lets write a C program to convert a number from Binary number system(base 2) to Decimal number system(base 10), using while loop.

Note: Binary number system can be derived by base 2 to the power of whole numbers.

Example:
etc .. 2⁴, 2³, 2², 2¹, 2⁰

etc .. 2⁴ = 16, 2³ = 8, 2² = 4, 2¹ = 2, 2⁰ = 1.

binary decimal number system

Expected Output for the Input

User Input:
Enter a Binary Number
1110

Output:
Decimal Equivalent of 1110 is 14

Explanation:

(2³ x 1) + (2² x 1) + (2¹ x 1) + (2⁰ x 0 )
= 8 + 4 + 2
= 14.

Video Tutorial: C Program To Convert Binary Number To Decimal Number, using While Loop

[youtube https://www.youtube.com/watch?v=UZMuZX_gtMs]

YouTube Link: https://www.youtube.com/watch?v=UZMuZX_gtMs [Watch the Video In Full Screen.]

Logic To Convert Binary Number To Decimal Number, using While Loop

In this C program we ask the user to enter / input a binary number. Using while loop we fetch digits of that user entered number one by one. If the fetched value is 1, then we check the place value and use pow() method to place it properly in the Binary number system. i.e., if fetched digit is from position 3, then we use pow(2, 3) to calculate its decimal equivalent value i.e., 2 x 2 x 2 = 8. And then add this value to previous value of variable dec.

Source Code: C Program To Convert Binary Number To Decimal Number, using While Loop

#include < stdio.h >
#include < math.h >

int main()
{
    long num;
    int  dec = 0, rem = 0, place = 0;

    printf("Enter a Binary Number\n");
    scanf("%ld", &num);

    printf("Decimal Equivalent of %ld is ", num);
    while(num)
    {
        rem = num % 10;
        if(rem)
        {
            dec = dec + (pow(2, place) );            
        }
        num = num / 10;
        place++;
    }
    printf("%d\n", dec);

    return 0;
}

Output 1:
Enter a Binary Number
1000
Decimal Equivalent of 1000 is 8

Output 2:
Enter a Binary Number
1111
Decimal Equivalent of 1111 is 15

We can even write the program like this:

#include < stdio.h >
#include < math.h >
int main()
{
    long num;
    int  dec = 0, rem = 0, place = 0;

    printf("Enter a Binary Number\n");
    scanf("%ld", &num);

    printf("Decimal Equivalent of %ld is ", num);
    while(num)
    {
        rem = num % 10;
        dec = dec + rem * ( pow(2, place) );
        num = num / 10;
        place++;
    }
    printf("%d\n", dec);

    return 0;
}

Output 1:
Enter a Binary Number
1011
Decimal Equivalent of 1011 is 11

Output 2:
Enter a Binary Number
10011
Decimal Equivalent of 10011 is 19

Number Systems

number systems

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert

C Program To Convert Decimal Number To Binary Number, using While Loop

Lets write a C program to convert a number from Decimal number system(base 10) to Binary number system(base 2), using while loop.

Note: Binary number system can be derived by base 2 to the power of whole numbers.

Example:
etc .. 2⁴, 2³, 2², 2¹, 2⁰

etc .. 2⁴ = 16, 2³ = 8, 2² = 4, 2¹ = 2, 2⁰ = 1.

binary decimal number system

Expected Output for the Input

User Input:
Enter a decimal number
14

Output:
Binary equivalent of 14 is 1110

Explanation:
If user enters num = 14

We keep on dividing the number 14 by 2.

14 / 2 = 7, reminder 0.
07 / 2 = 3, reminder 1.
03 / 2 = 1, reminder 1.

Decimal to binary

So Binary equivalent of 14 is 1110.

(2³ x 1) + (2² x 1) + (2¹ x 1) + (2⁰ x 0 )
= 8 + 4 + 2
= 14.

Video Tutorial: C Program To Convert Decimal Number To Binary Number, using While Loop

[youtube https://www.youtube.com/watch?v=lSn6E5pv7pc]

YouTube Link: https://www.youtube.com/watch?v=lSn6E5pv7pc [Watch the Video In Full Screen.]

Logic To Convert Decimal Number To Binary Number, using While Loop

In this C program we ask the user to enter / input a decimal number. Using while loop we calculate the reminder and add it to variable bin. We make use of variable place to position the reminder based on number system – unit, ten, hundred, thousand, ten thousand etc.

Source Code: C Program To Convert Decimal Number To Binary Number, using While Loop

#include < stdio.h >

int main()
{
    int num, bin = 0, rem = 0, place = 1;

    printf("Enter a decimal number\n");
    scanf("%d", &num);

    printf("\nBinary equivalent of %d is ", num);
    while(num)
    {
        rem   = num % 2;
        num   = num / 2;
        bin   = bin + (rem * place);
        place = place * 10;
    }
    printf("%d\n", bin);

    return 0;
}

Output 1:
Enter a decimal number
14

Binary equivalent of 14 is 1110

Output 2:
Enter a decimal number
15

Binary equivalent of 15 is 1111

Output 3:
Enter a decimal number
19

Binary equivalent of 19 is 10011

Output 4:
Enter a decimal number
8

Binary equivalent of 8 is 1000

Output 5:
Enter a decimal number
41

Binary equivalent of 41 is 101001

Number Systems

number systems

For list of all c programming interviews / viva question and answers visit: C Programming Interview / Viva Q&A List

For full C programming language free video tutorial list visit:C Programming: Beginner To Advance To Expert