The function example and source code of string.trim() function in java

The function of trim(): removes the spaces at the beginning and end of the string.

 public static void main(String arg[]){String a=" hello world ";String b="hello world";System.out.println(b.equals(a));a=a.trim();//Remove the spaces at the beginning and end of the string System.out.println(a.equals(b));}

Execution results:

a: hello world ,false
a:hello world,true

Source code of trim():

 public String trim() {
 int arg0 = this.value.length;
 //Get the length of this string
 int arg1 = 0;
     //Declare an int value and assign a value of 0
 char[] arg2;
      //Declare a char array
 for (arg2 = this.value; arg1 < arg0 && arg2[arg1] <= 32; ++arg1) {
 // Assign this character array to arg2 character array (the bottom layer of a java string is a character array, and this character array is the value attribute of the String class);
 //Why is less than or equal to 32, please refer to the ASCII code table. ASCII table 32 represents a space, and there are tab tab characters below 32, /n newline characters, /r carriage return characters, /b backspace, etc.
 //If a string is "123", then after the method is run, the value of arg1 will be assigned to 1.
 ;
 }
 while (arg1 < arg0 && arg2[arg0 - 1] <= 32) {
 --arg0;
 //If a string is "123", then after the method is run, arg0 will be assigned a value of 4
 }
 return arg1 <= 0 && arg0 >= this.value.length ? this : this.substring(arg1, arg0);
 //arg1==1, so go back. this.substring(1,4)
 //Including head but not tail, the result is "123"
 }

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