// this example illustrates the way to convert a string from lower case to upper case

#include <stdio.h>    // for printf, scanf
#include <stdlib.h>   // for malloc, free
#include <ctype.h>    // for is_lower

int string_length(char * my_string)
{
  int counter = 0;
  while(1)
  {
    if (my_string[counter] != 0)
    {
      counter++;
    }
    else
    {
      break;
    }
  }

  return counter;
}


char * convert_to_upper_case(char * text)
{
  int length = string_length(text);

  int i;
  char * temp = (char *) malloc(sizeof(char) * (length+1));
  for (i=0; i< length; i++)
  {
    if(islower(text[i]))
    {
      temp[i] = text[i] - 32;
    }
    else
    {
      temp[i] = text[i];
    }
  }
  temp[length] ='\0';
  return temp;
}


int main()
{	
  char * text = (char *) malloc(sizeof(char) * 1000);
  char * text_capital;
  printf("please enter a string (the length should be less than or equal to 1000):\n");
  scanf("%s", text);

  text_capital = convert_to_upper_case(text);
  printf("the upper-case version of %s is %s\n", text, text_capital);
  free(text);
  free(text_capital);
}