#include "stdio.h"

int main(void)
{
int i = 0;
char s[80] = "AadD";


while (s[i] != '\0')
{
if (s[i] <= 'Z' && s[i] >= 'A')
s[i] = 'z' + 'a' + s[i];//如果改成这样s[i] = 'z' + 'a' :当为A和D时,怎么不能得到s[i] = 'z' + 'a' 的值
i++;
}
puts (s);
printf ("\n%c,%c,%c,%c\n", s[0], s[1], s[2], s[3]);
printf ("%d,%d,%d,%d", s[0], s[1], s[2], s[3]);
getch ();
return 0;
}

另ASCII中的字符转换是怎么样的? 比如从'A'转到'>'

不懂你的意思？？