Scanf, printf, fscanf, fprintf, sscanf, sprintf, etc.

(1) scanf and printf

 

Scanf slaveStdinInput is accepted, and the data is output to the variable in the specified format.

The original scanf function is: int scanf (_ Const char * _ restrict _ format,...) _ WUR, where... is a variable parameter with a variable length. for example, scanf ("% d % F", & I, & F) assigns a value to the variables I and F.

 

Printf willVariableOutputStdout

The prototype of the printf function is: int printf (_ Const char * _ restrict _ format,...), For example: printf ("% d", I) indicates to pass the value of variable I to the standard output.

(2) fscanf and fprintf

 

Fscanf slaveFileAccept input, output data in the specified formatVariable.

The fscanf function is prototype: int fscanf (File * _ restrict _ stream,_ Const char * _ restrict _ format,...) _ WUR, for example, fscanf (FP, "% d % F", & I, & F) indicates the current data represented by the file pointer, usually one line is output to the variables I and F.

 

Fprintf willVariableOutputFile

The fprintf function is prototype: int fprintf (File * _ restrict _ stream,_ Const char * _ restrict _ format,...), Such as fprintf (FP, "% d % F", I, F );

 

 

(3) sscanf and sprintf

 

Sscanf slaveStringAccept input, output data in the specified formatVariableTo convert strings to other variables.

The sscanf function is prototype: int sscanf (_ const char * _ restrict _ s, _ const char * _ restrict _ format ,...) _ Throw. For example, sscanf (P, "% d", & I) converts the string represented by P to an integer variable and assigns it to I, if the pointer P points to the string "12345", then I = 12345.

 

Sprintf outputs variables in the specified formatStringTo convert other types of variables into strings.

Sprintf function prototype: int sprintf (char * _ restrict _ s, _ const char * _ restrict _ format ,...) _ Throw, for example, sprintf (P, "% d", I). If I = 12345, the pointer P points to the memory and stores the string "12345 ".

 

 

These functions also support regular expressions, which are very powerful and often used.

 

Relevant information is worth reading:

 

Sprintf, how much do you know? Http://blog.csdn.net/sjf331/archive/2005/04/07/339254.aspx

Regular Expressions in sscanf, scanf, and fscanf

Http://ybmmwjl.blog.163.com/blog/static/656387812010102691254484/

Scanf and sscanf

Http://wenku.baidu.com/view/3e3250160b4e767f5acfce85.html