c1_预处理01.txt

嵌入式C语言培训课件

#define LETTER 1
void main()
{
	char str[20] = "CLanguage";
	char c;
	int i = 0;
	while ((c=str[i]) != '\0')
	{
		i ++;
#if LETTER
		if ((c >= 'a') && (c <= 'z'))
		{
			c = c- 32;
		}
#else
		if (c>='A' && c <= 'Z')
		{
			c = c+32;
		}
#endif
		printf("%c", c);
	}
	printf("\n");
//#if defined LETTER
//#undef LETTER
//#endif

#if LETTER
	printf("dfjk\n");
#endif
	
}