1.判断一个字符是否是可以打印的字符判断：
void isgraph_test(void)
{
unsigned char s[] = "abcdef\t\n\rddd+^";
int i = 0;
while(s[i] != '\0')
{
if(isgraph(s[i]))
{
printf("%c OK\n",s[i]);
}
else
{
printf("%c NOT OK\n",s[i]);
}
i++;
}
}
执行结果：
很简单了，能够看得见的就是true，看不见的就是False。
2.大小写的判断，这两个其实只要记住一个即可，除非检测对象不是字母。以前感觉Python有这些功能很强大，看起来C也照样强大。
void islower_test(void)
{
unsigned char s[] = "ABCFxcdefSSK123x";
int i = 0;
while(s[i] != '\0')
{
if(islower(s[i]))
{
printf("%c is lower.\n",s[i]);
}
else
{
printf("%c is not lower.\n",s[i]);
}
i++;
}
}
执行结果：
3.是否是打印字符
void isprint_test(void)
{
unsigned char s[] = "ando423!@#$%^&*()\1\2\3\n\r\t";
int i = 0;
while(s[i] != '\0')
{
if(isprint(s[i]))
{
printf("%c is print.\n",s[i]);
}
else
{
printf("%c is not print.\n",s[i]);
}
i++;
}
}
执行结果：
4.是否可以处理为空白
void isspace_test(void)
{
unsigned char s[] = " \t\n\b\0";
int i = 0;
while(s[i] != '\0')
{
if(isspace(s[i]))
{
printf("%c is space.\n",s[i]);
}
else
{
printf("%c is not space.\n",s[i]);
}
i++;
}
}
执行结果：
5.十六进制字符检查
void isxdigit_test(void)
{
unsigned char s[] = "1234567890abcdefABCDEFXSWF";
int i = 0;
while(s[i] != '\0')
{
if(isxdigit(s[i]))
{
printf("%c is x.\n",s[i]);
}
else
{
printf("%c is not x.\n",s[i]);
}
i++;
}
}
执行结果：
6.大小写的转换
void convert_test(void)
{
unsigned char s[] = "abcdeDDKKKSxxxFFF1123xxx";
unsigned char s1[sizeof(s)];
int i = 0;
while(s[i] != '\0')
{
printf("raw: %s\n",s);
while(s[i] != 0)
{
s1[i] = tolower(s[i]);
i++;
}
i = 0;
printf("lower: %s\n",s1);
while(s[i] != 0)
{
s1[i] = toupper(s[i]);
i++;
}
printf("upper isL %s\n",s1);
}
}
这个也让我想到了Python，看起来这个功能上Python是要简单一点。因为Python处理的是字符串，而C处理的是一个字符。
