01 #include<stdio.h>
02 
03 int main()
04 {
05     long int decimalNumber,remainder,quotient;
06 
07     int i=1,j,temp;
08 
09     char hexadecimalNumber[100];
10 
11     printf("Enter Decimal Number : ");
12     scanf("%ld",&decimalNumber);
13 
14     quotient = decimalNumber;
15 
16     while(quotient!=0)
17         {
18             temp = quotient % 16;
19 
20 //integer into character
21             if( temp < 10)
22                 temp =temp + 48;
23             else
24                 temp = temp + 55;
25             hexadecimalNumber[i++]= temp;
26             quotient = quotient / 16;
27         }
28 
29     printf("Hexadecimal value is : ");
30     for(j = i -1 ; j> 0; j--)
31         printf("%c",hexadecimalNumber[j]);
32 
33     return 0;
34 }

 OUTPUT :
 
 Enter Decimal Number : 451
 HexaDecimal value is : 1C3