What are the methods of converting decimal to hexadecimal in C language?

#include
int main() {
	long int decimalNumber,remainder,quotient;
	int i=1,j,temp;
	char hexadecimalNumber[100];
	printf("输入十进制数任意: ");
	scanf("%ld",&decimalNumber);
	quotient = decimalNumber;
	while(quotient!=0) {
		temp = quotient % 16;
		if( temp < 10)
		           temp =temp + 48; else
		         temp = temp + 55;
		hexadecimalNumber[i++]= temp;
		quotient = quotient / 16;
	}
	printf("十进制数的等效十六进制值 %d: ",decimalNumber);
	for (j = i -1 ;j> 0;j--)
	      printf("%c",hexadecimalNumber[j]);
	return 0;
}

#include
#include

int main()
{
      int decimal_number, remainder, hexadecimal_number = 0;
      int count;
      printf("Enter a Decimal Number:\t");
      scanf("%d", &decimal_number);	
      for(count = 0; decimal_number > 0; count++)
      {
            remainder = decimal_number % 16;
            hexadecimal_number = hexadecimal_number + remainder * pow(10, count);
            decimal_number = decimal_number / 16;
      }
      printf("\nHexadecimal Equivalent:\t%d\n", hexadecimal_number);
      return 0;
}

#include
#include

int decimal_to_hexadecimal(int x)
{
      int hexadecimal_number, remainder, count = 0;
      for(count = 0; x > 0; count++)
      {
            remainder = x % 16;
            hexadecimal_number = hexadecimal_number + remainder * pow(10, count);
            x = x / 16;
      }
      return hexadecimal_number;
}

int main()
{
      int decimal_number, result;
      printf("Enter a Decimal Number:\t");
      scanf("%d", &decimal_number);		
      result = decimal_to_hexadecimal(decimal_number);	
      printf("\nHexadecimal Equivalent:\t%d\n", result);
      return 0;
}