9_11.cpp

C程序参考,简单易懂,是初学者不可少的参考资料

#include<stdio.h>
#define LETTER 1
main()
{
    char c1,c2;
    c1=getchar();
    while(c1!=EOF)
    {
	#if LETTER
	    if(c1>='a'&&c1<='z')
		c1=c1-32;
	#else
	    if(c1>='A'&&c1<='Z')
		c1=c1+32;
	#endif
	c2=putchar(c1);
	c1=getchar();
     }
}