A-z and 0-9 form a 3-digit password. Please list all possible combinations in the console output. (java code implementation)

I'll post a code to you, which is incomplete and can express the meaning.

Package code segment;

Import java.util. *;

Common class sorting {

Static int count = 0；;

static char[] buf = { ' 1 '，' 2 '，' 3 '，' 4 '，' 5 '，' 6 '，' 7 '，' 8 '，' 9 '，' 0 '，' a '，' b ' }；

Static list & lt string & gtlist = new ArrayList & lt string & gt ();

public static void main(String[]args){ select(buf，list，3)；

for (String str : list) {

system . out . println(str)；

}

System.out.println ("total:"+count); }

Public static void select(char[] source, List & lt string & gt array list,

int num) {

int l = source.length

Char[] temp = new char [num];

System.arraycopy(source，0，temp，0，num)；

ArrayList.add (new string (temp))；);

for(int I = num； I & ltl；; i++) {

for(int j = 0； j & ltnumj++) {

char temp char = temp[j]；

temp[j]= source[I]；

ArrayList.add (new string (temp))；);

temp[j]= temp char；

}

}

}

public static void perm(char[] buf，int start，int end) {

If (start == end) {// When only one letter in the array needs to be fully arranged, it is output as an array.

for(int I = 0； I<= end; i++) {

system . out . print(buf[I])；

}

sort . count++；

system . out . println()；

} else {// Multiple letters are all arranged.

for(int I = start； I<= end; i++) {

char temp = buf[start]； //Swap the first element of the array with subsequent elements.

buf[start]= buf[I]；

buf[I]= temp；

perm(buf，start + 1，end)； //Recursive complete arrangement of subsequent elements

temp = buf[start]； //Restores the swapped array.

buf[start]= buf[I]；

buf[I]= temp；

}

}

}

}