java array, string concatenation

1. 数组实现拼接
 int[] arr ={11,22,33,44,55,66};
 System.out.print("[");
 for (int i = 0; i <arr.length ; i++) {
     if (i==arr.length-1){
         System.out.print(arr[i]);
     }else {
         System.out.print(arr[i]+", ");
     }
 }
 System.out.println("]");


2. String实现字符串拼接
 String[] arr={"11","22","33","44","55"};
 String s="[";
 for (int i = 0; i <arr.length ; i++) {
     if (i==arr.length-1)
     s+=arr[i];
     else {
         s+=arr[i]+", ";
     }
 }
 s+="]";
 System.out.println(s);String [] ss = { "11
3. StringBuilder achieve string concatenation

 StringBuilder s =new StringBuilder();
 s.append("[");
 for (int i = 0; i <ss.length ; i++) {
     if (i==ss.length-1){
         s.append(ss[i]);
     }else {
         s.append(ss[i]).append(", ");
     }
 }
 s.append("]");
 String s1 =s.toString();
 System.out.println(s1);
 4.数组实现反转
 int[] arr={11,22,33,44,55,66};
 for (int start=0,end=arr.length-1;start<=end;start++,end--){
     int tmp = arr[start];
     arr[start]=arr[end];
     arr[end]=tmp;
 }
 System.out.print("[");
 for (int i = 0; i <arr.length ; i++) {
    if (i==arr.length-1){
        System.out.print(arr[i]);
    } 
    The else { 
        of System.out.print (ARR [I] + ","); 
    } 
} 
System.out.println ( "]"); 
5. The string for reversing 
Scanner sc = new Scanner (System.in) ; 
System.out.println ( "Please enter the string:"); 
string sc.nextLine S = (); 
string S1 = ""; 
for (int I = s.length () -. 1; I> = 0; I -) { 
     S1 + = s.charAt (I); 
} 
System.out.println (S1); 
6. The use StringBuilder for reversing 
Scanner Scanner new new SC = (the System.in); 
System.out.println ( "Please input string: "); 
string sc.nextLine S = (); 
the StringBuilder the StringBuilder new new S2 = (S); 
s2.reverse (); 
string s2.toString S3 = (); 
System.out.println (S3);