islower(ch)为什么能等价于ch>='a' &&ch<='z'
#include "stdio.h"#include "ctype.h"
char myupper(char ch)
{if(islower(ch)) ch=ch-32;
return ch;
}
main()
{
char ch;
while((ch=getchar())!='@')
{ch=myupper(ch);
putchar(ch);}
}
islower(ch)为什么能等价于ch>='a' &&ch<='z'
