iscsym ( )【C语言库函数源代码】

【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;

}