Char vs String in Java?

Question

I am learning Java this year as part of the AP Computer Science curriculum, and while I was reading about "Char" and "String", I could not understand why it would be possible to use "Char" and only be able to store one character, not just use "String" and be able to store much more. In short, what is the point "Char" if it can only store one character?

Answer 1

People mention memory problems that are valid, but I don't think this is a very important cause in 99% of cases. The important reason is that the Java compiler will tell you if you made a mistake, so you don’t have to figure it out yourself.

For example, if you want only 1 character for a variable, you can use char to store the value, and now no one can put anything else there without being an error. If you were to use String instead, there could be two characters in the string, even if you assumed it was not possible. In fact, the string can have 0 characters, which would be just as bad. Also, all of your code that uses String will have to say “get the first character of the string”, where it can just say “give me a character”.

An analogy (which perhaps doesn't make sense to you, unfortunately) would be: "Why should I say that Person has a Name , when can I say that Person has a list of Names ?" For the same reasons. If you want Person have one Name , then providing him with a Name list adds a lot of overhead.

Answer 2

You could consider this analogy:

You need one apple. Would you rather have one apple in your hand or a large box that could contain more apples, but should contain only one?

With the primitive char type, it is easier to work with the String class in situations where you need only one character. This is also much less overhead because the String class has many additional methods and information that it needs to store in order to be effective in processing multiple-character strings. Using the String class when you only need one character is basically redundant. If you want to read a variable of both types to get a character, this is the code that will do this:

 // initialization of the variables char character = 'a'; String string = "a"; // writing a method that returns the character char getChar() { return character; // simple! } char getCharFromString() { return string.charAt(0); // complicated, could fail if there is no character } 

If this code looks complicated, you can ignore it. The conclusion is that using String when you only need one character is excessive.

Basically, the String class is used when you need more than one character. You can also just create an array of char s, but then you would not have any useful methods of the String class, such as .equals() and .length() methods.

Answer 3

String - objects. Objects always go to dynamic storage. To store a single-character string will require at least a dozen bytes.

char (not char s) are primitives. They occupy a fixed amount of space (2 bytes). In situations where you need to process a single character, creating a one-character string is a waste of resources. Moreover, when you expect to see a single character, using strings will require checking that the data passed inside has exactly one character. This would be unacceptable in situations where you have to be very fast, for example, based on characters and output.

To summarize, you need char due

• Memory capacity - char less than String one character
• Processing speed - creation of objects carries service
• Program support . Knowing the type makes it easier for you and your code readers to know what data should be stored in the char variable.

Answer 4

char takes up less memory if you really only need one character. There are also several other applications for using a single character.

char is a primitive data type, and string is an object that comes with great overhead.

A string also consists of char , so that too.

Answer 5

Since char takes up less memory!

In addition, char is stored in memory and not as a reference value, so theoretically, it is faster to access char (you will understand that later)

*** Note. I once had the same thought when I started writing about why to use int, when you can use long and not worry about large numbers. This tells me that you are on your way to becoming a great programmer! :)

Answer 6

char is a primitive type, and String is a true Object . In some cases, when performance is a problem, it is possible that you want to use only primitives.

Another case when you want to use char is when you write Java 1.0 and you are tasked with creating the String class!

 public final class String implements java.io.Serializable, Comparable<String>, CharSequence { /** The value is used for character storage. */ private final char value[]; 

Answer 7

Everything in java can be reduced to primitive types. You can write any program with primitive types. So you need some kind of minimalist way to store text. A char is also just a byte, which is interpreted as a character.

Also, if you want all characters in a string to be executed, follow these steps:

 char[] chArr = str.toCharArray(); for(int i = 0 ; i < chArr.length ; i++) { //do something with chArr[i]; } 

This would be much more inconvenient if we fine-tune the exact character from the string.

Answer 8

There are many answers here. Although memory problems are valid, you should understand that there are times when you want to directly manipulate characters. word staircase

where you are trying to turn one word into another by changing one character at a time, I would like to do this in a programming class. Having a char type allows you to manipulate a character one at a time. It also allows you to assign an int to char, which maps to your local character set.

You can do something like char c = 97; and it will print as a. You can do things like character increments from 97 to 122 to print all lowercase characters. This is sometimes really helpful.