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Write a java code to check if the given string is even or not? Eg. aabbcc, aacbbc is even string.
I was asked this program in one interview. Actually i did not understand what is frequency here.
For a string s of length n, consider s[0] XOR s[1] ... XOR s[n - 1] where [i] is the (i)th letter of the string. Use java.lang.String#charAt(int) in java to extract a character.
If that is zero you have an even string, else you have an odd string.
Test n % 2 first for an immediate pay rise: If that is not zero then there must be at least 1 occurrence of a character that appears an odd number of times.
Normally folk who wrote computer games in machine code as kids in the 1980s will ask this question as it seems obvious to them. I doubt it is any more: XOR was a very fast way of writing sprite images.
Depending on what the interviewer was asking, string frequency is either,
how many times a string is found in another string.
how many times a character is found in a string.
Related
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I'm trying to learn Java. My current assignment is to build a simple four function calculator..... this would be easy given if/else and/ or switch statements, but I'm supposed to build this using methods.
The original input has to be put in as a single string, so, in my mind, I'm going to have to take the single string and create substrings, then somehow convert these substrings into double values, while deleting whatever whitespace could possibly be between characters. My current idea is to somehow identify the "+,-,*, or /" within the string and divide into substrings before and after these values, using the appropriate defined method for whichever operator to do the calculations....
The problem is that I can't see a good way to divide these up into substrings or how to convert the numbers involved into double values. Anyone got any advice for me? Keep in mind, what we have gone through is pretty limited and I feel like I'm missing something REALLY simple out there.
You can split a string based on a particular character using str.split("\\+"), for example. You can convert the split pieces of the string to doubles by using Double.parseDouble(str);
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So I'm working on a school project and it includes a Combined Gas Law calculator where the user may input the temperature in °celsius (e.g. 1°C) and the code converts it to kelvin; if the user's input is in kelvin already, it does not do that and continues with the equation. So does anyone know how I can separate the two data types into two different variables in Java?
You could split over a specific string (degree character for example), store in a String array and parse the first element. Something like this:
String str = "47°C"
String[] strArray = str.split("°");
int number = Integer.parseInt(strArray[0]);
Congratulations, you are working on something but not writing it's code. I can tell you a few tips about how to implement it's code.
You have a string that has some numbers in it, and also has unit. Try searching 'How to extract numbers from a string'. Now you have a number.
Find the unit in the string by looking the last character in the string.
If the condition is ok for your homework, calculate the new value.
Print the result.
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I'm making a textbook indexer and I'm formatting the output file. there are periods between the word and its frequency.
desired textfile output:
word..............25:
word...............3:
word...............2:
I'm trying to get the lines to be aligned to the : but I can't get it under the semicolon if the numbers are more than 1 digit.
Does anybody have any ideas for java string formatting for the desired output?
for reference the biggest word is 23 characters and it's frequency is 1.
Since in the comment, the OP attempted to use String.format(), here is an approach to consider. Rather than trying to get the number to align right with the "%23d", align the word and the count separately.
String.format("%-23s%2d:", getWord(), count);
The %-23d will format the getWord() in 23 spaces, left aligned, then the %2d will right align the "count".
Example output:
Hello...................9:
Goodbye................42:
whatever...............17:
Note I just used the same .replace() approach as the OP for quickness sake.
See this attempt here at ideone.com
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I'm working on a calculator, it should receive the input as a String and then perform the calculation, outputting the result.
For example, the input could be
((23+17) mod 7 × 4 AND 13
and the output would be 4, as expected.
How can I parse the input, to extract all the operands and perform the calculation ?
The other answers are just "how to set a variable to this result" but if you're actually looking to parse input, you should refer to this:
Equation (expression) parser with precedence?
There are a number of ways to go about solving this kind of problem, and a number of algorithms for doing so. Some of them are stack based, some perform a descent of the "tree", and I can even think of a (somewhat) convoluted way to OOP-ize it. I would start with the link above.
You can use regular expressions to parse the string.
http://docs.oracle.com/javase/1.4.2/docs/api/java/util/regex/Pattern.html
First you have to look for the most important arguments like [() - parentheses], then less [*/] and [+-]. You have to divide the whole string into parts.
Examples:
Simple calculator (bottom of the page)
Another calculator
Both in Java.
see this page for your reference.
http://www.tutorialspoint.com/java/java_basic_operators.htm
all operators in java are explained very clearly.
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I don't know a single bit about regex. I want to find certain occurences in my java project using eclipse. The words could be
SEQ_NUM
SEQNUM
SEQNUMBER
SEQ_NUMBER
searching strings based on word "seq" would generate lots of results. What regex should suffice my problem?
These four cases can be combined to the following regex:
SEQ_?NUM(BER)?
SEQ_?NUM(BER)?
SEQ - must exist
_? - '_' can appear 0 or 1 time
NUM - NUM must also exist
(BER)? - 'BER' can appear 0 or 1 time
This should work for you.
SEQ[_NUMBER]+