program3_04.c

C语言入门经典一书的所有代码。书上面的所有代码均在此。希望大家喜欢

/* Program 3.4 Converting uppercase to lowercase */
#include <stdio.h>

int main(void)
{
  char letter = 0;                        /* Stores a character               */

  printf("Enter an uppercase letter:");   /* Prompt for input                 */
  scanf("%c", &letter);                   /* Read a character                 */

  /* Check whether the input is uppercase */
  if(letter >= 'A')                       /* Is it A or greater?              */
    if (letter <= 'Z')                    /* and is it Z or lower?            */
    {                                     /* It is uppercase                  */
      letter = letter - 'A'+ 'a';         /* Convert from upper- to lowercase */
      printf("You entered an uppercase %c\n", letter);
    }
    else                                  /* It is not an uppercase letter    */
      printf("Try using the shift key, Bud! I want a capital letter.\n");
  return 0;
}