I. Possible combinations:
(1) const char * P
(2) Char const * P
(3) char * const P(4) const char ** P
(5) Char const ** P
(6) char * const * P
(7) Char ** const P
Of course, there are several cases of inserting a const in (5), (6), and
Constraints for assigning values according to ansi c:
1. Both operands are pointers to compatible types with or without delimiters.
2. the type pointed to by the Left pointer must have all the qualifiers of the type pointed to by the right
1. JudgmentCharacterWhether the string is only a number:
1> use Java built-in functions
Public static Boolean isnumeric (string Str ){
For (INT I = Str. Length (); -- I> = 0 ;){
If (! Character. isdigit (Str. charat (I ))){
Return
There are many C procedures, in the communication with the new members of the project found that generally for Char *s1 and Char s2[] know there are misunderstandings (think no difference), resulting in sometimes "difficult to understand" error. A
Conversion between string, CString, char *
Int to CString:CString. Format ("% d", int );...............................String to CStringCString. format ("% s", string. c_str ());C_str () is indeed better than data.....................................
The transformation between string,cstring,char*
int Turn CString:Cstring.format ("%d", int);...............................String Turn CStringCstring.format ("%s", String.c_str ());Using C_str () is indeed better than data ()........................
Charvarcharvarchar2 differences: 1. the length of CHAR is fixed, while the length of VARCHAR2 can be changed. For example, the storage string "abc", for CHAR (20 ), it indicates that the characters you store will occupy 20 bytes (including 17 null
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