toupper函数及一些小程序

    

toupper
    

  原型：extern int toupper(int c);
  
  用法：#include <ctype.h>
  
  功能：将字符c转换为大写英文字母
  
  说明：如果c为小写英文字母，则返回对应的大写字母；否则返回原来的值。
  
  举例：


      // toupper.c
      
      #include <syslib.h>
      #include <ctype.h>

      main()
      {
        char *s="Hello, World!";
        int i;
        
        clrscr();        // clear screen
        printf("%s
",s);
        for(i=0;i<strlen(s);i++)
        {
          putchar(toupper(s[i]));
        }
        
        getchar();
        return 0;
      }

//---------------------------------1
#include <stdio.h>
#include<stdlib.h>
void main()
{
    printf("0 & 0 is %d
", 0 & 0);
    printf("0 & 1 is %d
", 0 & 1);
    printf("1 & 1 is %d
", 1 & 1);
    printf("1 & 2 is %d
", 1 & 2);
    printf("15 & 127 is %d
", 15 & 127);
    system("pause");
}
//------------------------------2
#include <stdio.h>
#include<stdlib.h>
void main()
{
    int value = 0xFF;

    printf("The inverse of %X is %X
", value, ~value);
    system("pause");
}
//-------------------------------3
#include <stdio.h>
#include<stdlib.h>
void main()
{
    printf("0 | 0 is %d
", 0 | 0);
    printf("0 | 1 is %d
", 0 | 1);
    printf("1 | 1 is %d
", 1 | 1);
    printf("1 | 2 is %d
", 1 | 2);
    printf("128 | 127 is %d
", 128 | 127);
    system("pause");
}
//------------------------------------4
#include <stdio.h>
#include<stdlib.h>
void main()
{
    printf("0 ^ 0 is %d
", 0 ^ 0);
    printf("0 ^ 1 is %d
", 0 ^ 1);
    printf("1 ^ 1 is %d
", 1 ^ 1);
    printf("1 ^ 2 is %d
", 1 ^ 2);
    printf("15 ^ 127 is %d
", 15 ^ 127);
    system("pause");
}
//------------------------------------5
#include <stdio.h>
#include<stdlib.h>
void main()
{
    printf("The letter is %c
", 'A');
    printf("The letter is %c
", 65);
    system("pause");
}
//---------------------------------------6
#include <stdio.h>
#include<stdlib.h>
void main()
{
    char letter;

    int vowel_count = 0;
    int consonant_count = 0;

    for (letter = 'A'; letter <= 'Z'; letter++)
        switch (letter) {
        case 'A':
        case 'E':
        case 'I':
        case 'O':
        case 'U': vowel_count++;
            break;
        default: consonant_count++;
    };

    printf("The number of vowels is %d
", vowel_count);
    printf("The number of vowels is %d
", consonant_count);
    system("pause");
}
//------------------------------------------------------------7
#include <stdio.h>
#include <conio.h>
#include <ctype.h>
#include <stdlib.h>

void main()
{
    char letter;

    do {
        printf("A Display directory listing
");
        printf("B Display disk information
");
        printf("C Change system date
");
        printf("Q Quit
");
        printf("Choice: ");

        letter = getchar();
        letter = toupper(letter);

        if (letter == 'A')
            system("DIR");
        else if (letter == 'B')
            system("CHKDSK");//不能用
        else if (letter == 'C')
            system("DATE");
    } while (letter != 'Q');
    system("pause");
}