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

printf("The inverse of %X is %X\n", value, ~value);
system("pause");
}
//-------------------------------3
#include <stdio.h>
#include<stdlib.h>
void main()
{
printf("0 | 0 is %d\n", 0 | 0);
printf("0 | 1 is %d\n", 0 | 1);
printf("1 | 1 is %d\n", 1 | 1);
printf("1 | 2 is %d\n", 1 | 2);
printf("128 | 127 is %d\n", 128 | 127);
system("pause");
}
//------------------------------------4
#include <stdio.h>
#include<stdlib.h>
void main()
{
printf("0 ^ 0 is %d\n", 0 ^ 0);
printf("0 ^ 1 is %d\n", 0 ^ 1);
printf("1 ^ 1 is %d\n", 1 ^ 1);
printf("1 ^ 2 is %d\n", 1 ^ 2);
printf("15 ^ 127 is %d\n", 15 ^ 127);
system("pause");
}
//------------------------------------5
#include <stdio.h>
#include<stdlib.h>
void main()
{
printf("The letter is %c\n", 'A');
printf("The letter is %c\n", 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\n", vowel_count);
printf("The number of vowels is %d\n", 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\n");
printf("B Display disk information\n");
printf("C Change system date\n");
printf("Q Quit\n");
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");
}