Go notes (3) usage of go language FMT package

Introduce

fmt Is a common library for input and output
stay fmt package , There are two kinds of methods for formatting input and output ：scan and print
Respectively in scan.go and print.go In file

print： Output function

print Series is mainly used for output , It mainly includes three methods ：

print： Output content directly ,  Don't wrap  , Cannot format output .
printf：  Format the text output as specified .
println： Can be behind the output   Add line breaks  .

package main 

import "fmt" 
func main() {
     
//  When entering multiple values at once  Println  There's a space in the middle , Can wrap lines automatically  
    fmt.Println("Hello", "Println") 
//  When entering multiple values at once  Print  No middle space ,Print  No line wrapping ; 
    fmt.Print("Hello", "Print") 
// Printf  Is to format the output , In many scenarios  Println  More convenient ,Printf I won't change lines  
    fmt.Printf("Hello Printf %s", "AAA") 
}
// Hello Println 
// HelloPrintHello Printf AA

print.go It's defined in the file 9 A function
this 9 A function , According to two dimensions, functions can be divided according to two dimensions

   // If you put  Print  Understood as core keywords , Then the suffix followed by " f " and " ln " as well as "", Focus on the final result of the output content ; If the suffix is " f ",  Specify the format  If the suffix is " ln ",  There is a newline character .
   Println、Fprintln、Sprintln  Line breaks will be added when outputting content ; 
   Print、Fprint、Sprint  Output content without line breaks ; 
   Printf、Fprintf、Sprintf  Format the text output as specified .
   // If you put  Print  Understood as core keywords , Then the prefix in front has " F " and " S " as well as "", Focus on the goal of output content （ terminal ）; If the prefix is " F ",  Specify the  io.Writer  If the prefix is " S ",  Is output to string 
   Print、Printf、Println  Output content to standard output os.Stdout; 
   Fprint、Fprintf、Fprintln  Output content to the specified io.Writer;    
   Sprint、Sprintf、Sprintln  Output content to string 

scan: Output function

scan Series is mainly used to input
Example: get user input in the interactive interface

package main 

import "fmt" 

func main() {
     
     var name string 
     fmt.Print(" Enter your name :") 
     fmt.Scan(&name) 
     fmt.Printf(" The name you entered is ：%s", name) 
}
// Enter your name : Wang Jingze  
// The name you entered is ： Wang Jingze 
// It is worth noting that ,Scan  You need to use  &, Otherwise, it will be regarded as direct transmission .

scan.go It's defined in the file 9 A function ：
this 9 Functions can scan formatted text to generate values . It can also be explained according to two dimensions .

/* If you put " Scan " Understood as core keywords , Then the suffix followed by " f " and " ln " as well as "",  Focus on the results of the input ; If the suffix is " f ",  Specify the format  If the suffix is " ln ",  There is a newline character */

Scanln、Fscanln、Sscanln  Stop when reading line breaks , And ask for one line of all entries at a time ; 
Scan、Fscan、Sscan  Don't pay attention to line breaks when reading content ; 
Scanf、Fscanf、Sscanf  Read from formatted text .

/* If you put " Scan " Understood as core keywords , Then the prefix in front has " F " and " S " as well as "",  Focus on the source of input content （ terminal ）; If the prefix is " F ",  Specify the  io.Reader  If the prefix is " S ",  Is read from the string */

Scan、Scanf、Scanln  From standard input os.Stdin Read text ; 
Fscan、Fscanf、Fscanln  From the specified io.Reader Interface reads text ; 
Sscan、Sscanf、Sscanln  Read text from a parameter string .