strstr

strstr(const char *s1, const char *s2);

find s2 from s1, search until 0

ex:

char a[100] = "bbbbaaaa";

a[2]= 0;

printf("%d\n", strstr(a, "a"));

---> can not find

friend class

ex:

if A class wants B class can access A's protected method,

A must define B as its friend class

Programming: Principles and Practice using C++

new book

void parameter

in c,

int a()  &  int a(void) are different

a() can accept an infinite number of parameters,

a(void) can accept zero parameter

function pointer in c++

testFunPtr is not a static function 

testFunPtr2 is a static function

correct:

int (com_scsi_command_driver::*pt2Function)()=       &com_scsi_command_driver::testFunPtr;

int (*pt2Function)()= 

&com_scsi_command_driver::testFunPtr2;

wrong:

int (*pt2Function)()= &com_scsi_command_driver::testFunPtr;

file IO

in fcntl.h

O_RDONLY

typeof

get type:

ex:
typeof(int) intVar1=1;
typeof(intVar1) intVar2=intVar1;
typeof(int*) intPtrVar1=&intVar1;
typeof(intPtrVar1) intPtrVar2=intPtrVar1;
printf("%d %d %d %d\n", intVar1, intVar2, *intPtrVar1, *intPtrVar2);

result: 1 1 1 1

pragma pack

pragma pack(1):

#pragma pack()
回到預設值，在32-bit的系統上預設為pack(4)

little endian & big endian

how to know big endian or little endian?


#include

#ifdef __BYTE_ORDER
# if __BYTE_ORDER == __LITTLE_ENDIAN
# define I_AM_LITTLE_ENDIAN
# else
# if __BYTE_ORDER == __BIG_ENDIAN
# define I_AM_BIG_ENDIAN
# else
Error: unknown byte order!
# endif
# endif
#endif /* __BYTE_ORDER */

uint64_t

include stdint.h

typedef signed char int8_t
typedef unsigned char uint8_t
typedef signed int int16_t
typedef unsigned int uint16_t
typedef signed long int int32_t
typedef unsigned long int uint32_t
typedef signed long long int int64_t
typedef unsigned long long int uint64_t

the website about c

http://www.cprogramming.com

coding book

Writing Secure Code

code complete 

static function

in c:

the scope of function is limited to the file

size for array & pointer

char str[100];

char *str2=str;

sizeof(str)  

--->   100

sizeof(str2)

---->  4

%u

%u:  for unsigned int

fopen , fwrite

fopen

r or rb

Open file for reading.

w or wb

Truncate to zero length or create file for writing.

a or ab

Append; open or create file for writing at end-of-file.

r+ or rb+ or r+b

Open file for update (reading and writing).

w+ or wb+ or w+b

Truncate to zero length or create file for update.

a+ or ab+ or a+b

Append; open or create file for update, writing at end-of-file.

fwrite:

size_t fwrite ( const void * ptr, size_t size, size_t count, FILE * stream );

int fseek(FILE *stream, long offset, int whence)

sets the file position indicator for the stream pointed to by stream

If whence is set to SEEK_SET, SEEK_CUR, or SEEK_END, the offset is relative to the start of the file, the current position indicator, or end-of-file, respectively

long ftell(FILE *stream)

obtains the current value of the file position indicator for the stream pointed to by stream.

struct, array, pointer

ex:

struct people{

        int age;

        int height;

};

struct people a[10];

&a: bffff988  a:bffff988  &a[0]: bffff988  &a[1]:bffff990  (a+1):bffff990

because the size of struct people is 8,  (a+1)= &a[1]- &a[0]= bffff988+ 8= bffff990

struct people *b=a;

b+1 equals a+1

b[1] equals a[1]

fseek

reposition a file-position indicator in a stream

#include <stdio.h>

int fseek(FILE *stream, long offset, int whence);

whence:

describe the location in the file to which offset is relative

ex:

SEEK_SET:

relative to the beginning of the file

fscanf

nt fscanf ( FILE * stream, const char * format, ... );
the function returns the number of items succesfully read

fgets

char* fgets( char *str,  int num,  File  *stream )

read one line