Java Program to Generate All Possible Combinations Out of a, b, c, d, e

This is a java program to generate and print all possible combinations out of a, b, c, d, e. The trick here is to start with one letter combinations, then with two letter combinations and so on.

Here is the source code of the Java Program to Generate All Possible Combinations Out of a, b, c, d, e. The Java program is successfully compiled and run on a Windows system. The program output is also shown below.

  1. //This is a java program to print all possible combinations out of a, b, c, d, e
  3. public class All_Possible_Combinatons 
  4. {
  5.     static void printCombinations(char[] sequence, int N) 
  6.     {
  7.         char[] data = new char[N];
  8.         for (int r = 0; r < sequence.length; r++)
  9.             combinations(sequence, data, 0, N - 1, 0, r);
  10.     }
  12.     static void combinations(char[] sequence, char[] data, int start, int end,
  13.             int index, int r) 
  14.     {
  16.         if (index == r) 
  17.         {
  18.             for (int j = 0; j < r; j++)
  19.                 System.out.print(data[j] + " ");
  20.             System.out.println();
  21.         }
  23.         for (int i = start; i <= end && ((end - i + 1) >= (r - index)); i++) 
  24.         {
  25.             data[index] = sequence[i];
  26.             combinations(sequence, data, i + 1, end, index + 1, r);
  27.         }
  28.     }
  30.     public static void main(String args[]) 
  31.     {
  32.         char[] sequence = { 'a', 'b', 'c', 'd', 'e' };
  33.         System.out.print("The combinations are: ");
  34.         printCombinations(sequence, sequence.length);
  35.     }
  36. }


$ javac
$ java All_Possible_Combinatons
The combinations are: 
a b 
a c 
a d 
a e 
b c 
b d 
b e 
c d 
c e 
d e 
a b c 
a b d 
a b e 
a c d 
a c e 
a d e 
b c d 
b c e 
b d e 
c d e 
a b c d 
a b c e 
a b d e 
a c d e 
b c d e

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Youtube | Instagram | Facebook | Twitter