CTechnotips: Decimal to hexadecimal conversion in c language

Hexadecimal number system: It is base 16 number system which uses the digits from 0 to 9 and A, B, C, D, E, F.

Decimal number system:

It is base 10 number system which uses the digits from 0 to 9

Decimal to hexadecimal conversion method:

Following steps describe how to convert decimal to hexadecimal

Step 1: Divide the original decimal number by 16

Step 2: Divide the quotient by 16

Step 3: Repeat the step 2 until we get quotient equal to zero.

Equivalent binary number would be remainders of each step in the reverse order.

Decimal to hexadecimal conversion example:

For example we want to convert decimal number 900 in the hexadecimal.

Step 1:  900 / 16  Remainder : 4 , Quotient : 56

Step 2:   56 / 16  Remainder : 8 , Quotient : 3

Step 3:    3 / 16  Remainder : 3 , Quotient : 0

So equivalent hexadecimal number is: 384

That is (900)₁₀ = (384)₁₆

1. C code to convert decimal to hexadecimal

#include<stdio.h>

int main(){

    long int decimalNumber,remainder,quotient;

    int i=1,j,temp;

    char hexadecimalNumber[100];

    printf("Enter any decimal number: ");

    scanf("%ld",&decimalNumber);

    quotient = decimalNumber;

    while(quotient!=0){

         temp = quotient % 16;

      //To convert integer into character

      if( temp < 10)

           temp =temp + 48;

      else

         temp = temp + 55;

      hexadecimalNumber[i++]= temp;

      quotient = quotient / 16;

  }

    printf("Equivalent hexadecimal value of decimal number %d: ",decimalNumber);

    for(j = i -1 ;j> 0;j--)

      printf("%c",hexadecimalNumber[j]);

    return 0;

}

Sample output:

Enter any decimal number: 45

Equivalent hexadecimal value of decimal number 45: 2D

2. Easy way to convert decimal number to hexadecimal number:

#include<stdio.h>

int main(){

  long int decimalNumber;

  printf("Enter any decimal number: ");

  scanf("%d",&decimalNumber);

  printf("Equivalent hexadecimal number is: %X",decimalNumber);

  return 0;

}

Sample output:

Enter any decimal number: 45

Equivalent hexadecimal number is: 2D