Frequency Table (Bytes)

Project: Frequency Table (Bytes)

Write a program to generate a table of frequencies. The program should accept a stream on stdin and total the number of each byte seen. Once the stream has been read the program should print a tab-delimited table with columns for Byte Value (decimal), Byte Value (hexadecimal), Count, and Frequency. The frequency of each byte is the count for that byte divided by the total number of bytes in the file. Only print rows in the table for values with a byte count greater than 0.

Output

$ javac -Xlint FrequencyTableBytes.java $ java -ea FrequencyTableBytes < ../../data/text/USConstitution.txt Dec Hex Count Freq 10 0a 978 0.0202 32 20 10282 0.2129 34 22 2 0.0000 40 28 5 0.0001 41 29 5 0.0001 44 2c 565 0.0117 45 2d 51 0.0011 46 2e 290 0.0060 48 30 4 0.0001 ... 113 71 47 0.0010 114 72 2138 0.0443 115 73 2393 0.0495 116 74 3647 0.0755 117 75 747 0.0155 118 76 416 0.0086 119 77 347 0.0072 120 78 95 0.0020 121 79 492 0.0102 122 7a 31 0.0006 $ javac -Xlint FrequencyTableBytes.java $ java -ea FrequencyTableBytes < ../../data/text/UnicodeTest.utf8 Dec Hex Count Freq 10 0a 70 0.0276 32 20 243 0.0959 44 2c 11 0.0043 45 2d 2 0.0008 46 2e 7 0.0028 48 30 1 0.0004 49 31 3 0.0012 52 34 2 0.0008 55 37 3 0.0012 ... 230 e6 5 0.0020 231 e7 13 0.0051 232 e8 8 0.0032 233 e9 4 0.0016 234 ea 4 0.0016 235 eb 18 0.0071 236 ec 23 0.0091 237 ed 6 0.0024 239 ef 3 0.0012 240 f0 43 0.0170 $ javac -Xlint FrequencyTableBytes.java $ java -ea FrequencyTableBytes < ../../data/binary/RandomBytes1M.bin Dec Hex Count Freq 0 00 3869 0.0039 1 01 4021 0.0040 2 02 4006 0.0040 3 03 3886 0.0039 4 04 3930 0.0039 5 05 3886 0.0039 6 06 3865 0.0039 7 07 3965 0.0040 8 08 3870 0.0039 ... 246 f6 3965 0.0040 247 f7 3833 0.0038 248 f8 3944 0.0039 249 f9 3846 0.0038 250 fa 3985 0.0040 251 fb 3930 0.0039 252 fc 4008 0.0040 253 fd 4032 0.0040 254 fe 3933 0.0039 255 ff 3815 0.0038

Solution