【C语言库函数源代码】
【本程序在Dev C++ 4.9.9.2 下编译通过】
int my_iscsym(int c)
{
return (isalnum(c) || ( c == '_' ));
}//判断字符c是否为英文字母、数字和下划线
int main()
{
char ch = 'a';
if(my_iscsym(ch))
printf("%c is English, UnderLine Character or Number! /n",ch);
else
printf("%c is not a English, UnderLine Character and Number!/n",ch);
ch = '_';
if(my_iscsym(ch))
printf("%c is English, UnderLine Character or Number! /n",ch);
else
printf("%c is not a English, UnderLine Character and Number!/n",ch);
ch = '1';
if(my_iscsym(ch))
printf("%c is English, UnderLine Character or Number! /n",ch);
else
printf("%c is not a English, UnderLine Character and Number!/n",ch);
ch = '?';
if(my_iscsym(ch))
printf("%c is English, UnderLine Character or Number! /n",ch);
else
printf("%c is not a English, UnderLine Character and Number!/n",ch);
system("pause");
return 0;
}