C++

See the followingCodeAs shown in: Copy codeThe Code is as follows: # include # Include # Include # Include # Include # Include # Include Int main (INT argc, char * argv []) { Pid_t PID; Int Stat; Int exit_code; PID = fork ();If

1. System (execute shell command) Related functions Fork, execve, waitpid, popen Header file # Include Define functions INT system (const char * string ); Function Description System () calls fork () to generate sub-processes, which

We know that, During C ++ development, the class destructor used for base classes are generally virtual functions.But why? Here is a small example: There are two classes: Copy codeThe Code is as follows: class ClxBase { Public: ClxBase

1.When a target object is constructed using the source object of the same class, the copy constructor is called to construct the target object. If no copy constructor is defined, call the default copy function of the class to construct the target

PrototypeExtern char * strcat (char * dest, char * src ); Usage# Include FunctionAdd the string indicated by src to the end of dest (overwrite '\ 0' at the end of dest) and' \ 0 '. DescriptionThe memory areas specified by src and dest cannot

Before talking about function calls and return values, let's take a look at the issue of memory allocation in C ++. The C ++ compiler divides computer memory into code and data areas. Obviously, the code area stores program code, the data zone

I,The struct in C ++ expands the struct in C. It is no longer just a data structure that contains different data types. It has obtained too many functions. Can struct contain member functions? Yes!Can struct be inherited? Yes !!Can struct realize

Volatile means "easy to lose, easy to change ". The definition of this qualifier indicates to the compiler that the content of the variable may change due to modifications to other programs. When a variable is declared in a program, the compiler

The Code is as follows: Copy codeThe Code is as follows :/* * Bubble Sorting*/ Void BubbleSort (int arr [], int n) { Int temp; For (int I = 0; I { For (int j = I + 1; j { If (arr [I]> arr [j]) { Temp = arr [I]; Arr [I] = arr [j]; Arr [j] = temp; } }

I don't know when to start. I deliberately avoid changing the variable value in the for loop. It seems to be influenced by others' opinions, but I don't know the reason. However, sometimes it is not convenient to use other methods. I tried it

The Code is as follows: Copy codeThe Code is as follows: # include Int main () { Int pos = 2; Int neg =-2; Int mid = 0; If (pos) Printf ("pos./n "); If (neg) Printf ("neg./n "); If (mid) Printf ("mid./n "); Printf ("------------/n ");

Macro definition containing if When the macro definition contains if 1) define the following macro# Define DC (p) if (foo (p) fun (p) Used in the following Environment If (k> n) DC (k ); Else DC (n ); After macro replacement If (k> n) If

Personal implementation example: Copy codeThe Code is as follows: # include # Include # Define M 4 Int add (int a, int B ); Int sub (int a, int B ); Int mul (int a, int B ); Int div (int a, int B ); Int (* oper_func []) (int, int) = { Add, sub,

Use today FtruncateThe file is truncated, but it cannot achieve the expected results. After the file is truncated, the content is complex and the file size remains unchanged. After adding fflush () and rewind (), OK. The following is the test

The Code is as follows: Copy codeThe Code is as follows: # include # Include # Include # Include # Include # Include # Include # Include Char ** bak_argv; Int flag = 0; Void restart (void ); Void sighup_handler (int sig ); // Argv [0] use

Many times, when using some special libraries to compile executable programs, you need to add additional CFLAGS and LIBS. otherwise, the system will prompt that the specified header file cannot be found or "undefined reference... "error message. If

1) string operationsStrcpy (p, p1) copies the stringStrncpy (p, p1, n) copies the specified length stringStrcat (p, p1) Additional stringStrncat (p, p1, n) attaches a specified length stringStrlen (p) returns the string length.Strcmp (p, p1)

This is only part of instruction parsing, but it is the most Core. The complete command is AT + REG [admin] [2] [00: 0C: 29: AA: 0B: A7]. /*************************************** ************************* ** File: GetParameters. c ** Brief

In the project development project, if you can determine which file Which function has an error? That is, the lock error.That's good. This article is for this. First, let's take a look at the default output function of the file: File Information

The method for Traversing various data sets in C # is summarized here: 1. Enumeration type Copy codeThe Code is as follows: // traverse the enumerated names of the enumeration type samples. Foreach (string sp in Enum. GetNames (typeof (Sample ))) {