Question

please help me write function definition of this code ..thanks

/* Test change_case function. */

#include "nodep.h" //suppress deprecation warnings
#include <stdio.h> //printf(), scanf()
#include <conio.h> //getch()

#define _CRT_SECURE_NO_DEPRECATE 1
#define _CRT_NONSTDC_NO_DEPRECATE 1
#define ESC 27
#define LETTER_a 97
#define LETTER_z 122
#define LETTER_A 65
#define LETTER_Z 90

//function prototype:
char change_case(char cIn);

int main(void)
   {
   char cInput, cOutput;

   printf("Test change_case function...\n\n");
   printf("(Press ESC to exit, any other key to keep testing)\n");

   do
      {
      printf("\n\nEnter letter: ");
      cInput = _getche();
      cOutput = change_case(cInput);
      if(cOutput >= LETTER_A && cOutput <= LETTER_Z || cOutput >= LETTER_a && cOutput <= LETTER_z)
         printf("\nLetter with case changed = %c\n", cOutput); //endif
      }
   while(cInput != ESC);
   //enddowhile

   return 0;
   } //end program

//----------------------------------------------------------------------
//function definition:
char change_case(char cIn)
{

return change_case;
}

Answer 1

// change_case function implementation

char change_case(char cIn)

{

char change_case;

if(cIn >= LETTER_A && cIn <= LETTER_Z ){

change_case = (char)(97 + (int)(cIn - 'A'));   // as char a = 97 in ascii

}

if(cIn >= LETTER_a && cIn <= LETTER_z){

change_case = (char)(65 + (int)(cIn - 'a'));   // as char A = 65 in ascii

}

return change_case;

}