text: #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  /* run this program using the console pauser or add your own getch, system("pause") or input loop */
  
  char* usr_strdup (const char *s) {
      char *d = malloc (strlen (s) + 1);   // Space for length plus nul
      if (d == NULL) return NULL;          // No memory
      strcpy (d,s);                        // Copy the characters
      return d;                            // Return the new string
  }
  
  int main(int argc, char *argv[]) {
  	
  	char* str1="Hello World!";
  	
  	printf("The original string is %s at adress %d \n",str1, str1);
  	
  	char *d=usr_strdup(str1);
  	printf("The copied string is %s at address %d \n",d, d);
  	
  	
  	
  	return 0;
  }
  