Convert decimal number to hexadecimal

Write a program to convert decimal number to hexadecimal

The approach:-

1. Initialize a string array to hold the output hexadecimal string.
2. mod the input number by 16.  Map a hexadecimal digit based on the reminder value and append the output string.
3. Divide the number by 16 for next iteration.
4. Repeat steps 2 and 3 till number becomes 0.
5. Reverse the string to get the output hexadecimal sequence.

C++ program to convert decimal number to hexadecimal string

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <cmath>
using namespace std;

char* dec2hex(int n) {
 char* str = (char*)malloc(sizeof(32));
 char* hex_str = "0123456789abcdef";

 int count = 0;
 while ( n > 0 ) {
  int rem = n % 16;
  n = n / 16;
  str[count] = hex_str[rem];
  count++;
 }
 str[count] = '\0';

 // reverse the string
 int size = strlen(str) - 1;
 for ( int i = 0; i <= size/2; i++ ) {
  char ch = str[i];
  str[i] = str[size - i];
  str[size - i] = ch;
 }

 return str;
}

int main() {
 int n = 100;
 cout << dec2hex(n) << endl;
}

Output:-

64