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Java

Posted by ISAIAH S
ISAIAH S
1,409 Points

Isaiah.java:18: error: incompatible types: String cannot be converted to char char lotsOfStuff =...

My code: 

import java.io.Console;
public class Isaiah {
public static void main(String[] args) {
Console console = System.console();
String isName = console.readLine("Enter your name: ");
String fatal = "";
if(isName.equals("*ISAIAH*")) {
String secretCode =console.readLine("YOU HAVE ENTERED A SECRET CODE.\nHERE ARE YOUR OPTIONS.\n >IF YOU WANT TO CONTINUE:\nPRESS I.\n >IF YOU WANT TO EXIT:\n PRESS  E.\n  ");
if(secretCode.equalsIgnoreCase("E")){System.exit(0);
}else if(secretCode.equalsIgnoreCase("I")){
fatal = console.readLine(" WARNING:\nTHIS PROGRAM CAN BE FATAL.\nDO YOU STILL WANT TO     CONTINUE?\n\n  ");
if(fatal.equalsIgnoreCase("yes")){
console.readLine("Hello, %s.\n", isName);}else{System.exit(0);}}}
String number = console.readLine("Enter your favorite number:  ");
String mood = console.readLine("Enter your favorite mood:  "); 
String creature = console.readLine("Enter your favorite creature:  ");
String color = console.readLine("Enter your favorite color:  ");
char lotsOfStuff = number + mood + creature + color;
Character.toLowerCase(lotsOfStuff);
String isFavoriteThing = console.readLine("Is a %s, %s %s year old %s your favorite thing?  ", mood, color, number,creature);
if(isFavoriteThing.equalsIgnoreCase("no")) {console.readLine("Why not?  ");
console.printf("Well you should, it's all of your favorite stuff.\n\n");}
String computer = console.readLine("-------------------------------------------------\n\n  Do you want to have a talk with the computer?  ");
console.printf("\n---------------------------------------------\n\n\n");
String howYouDoing = "";if(computer.equalsIgnoreCase("yes")){
howYouDoing = console.readLine("Hello %s, how are you doing?\n  ", isName);
if(howYouDoing.equalsIgnoreCase("sad")) {console.readLine("Why are you %s, %s?  \n", howYouDoing, isName);}}}}

My error:

Isaiah.java:18: error: incompatible types: String cannot be converted to char                    
char lotsOfStuff = number + mood + creature + color;                                             
                                            ^                                                    
1 error

Thanks, ISAIAH S

2 Answers

Alexandru Doru Grosu
Alexandru Doru Grosu
2,753 Points
Alexandru Doru Grosu
Alexandru Doru Grosu
2,753 Points

Well that is expected.

Remember what I told you before, char (including its wrapper, Character) and String are two different types. 

Character.toLowerCase(lotsOfStuff);

Now you are trying to call a method that expects an argument of type char to be passed (i.e. a single character), with an argument that is of type String.

If you wish to convert a String to lower case, you will have to use the String method intended for this which is also called toLowerCase, however, you would have to call it on the String itself like so:

lotsOfStuff.toLowerCase();

Note: toLowerCase() will not modify the original String, but will instead return a copy of the original String but with all its contents in lower case. So if you want to make lotsOfStuff lower you would have to assign it to itself, like this:

// ...

String hello = "I AM UPPERCASE";
hello = hello.toLowerCase();
console.printf("%s", hello); // Will print "i am uppercase"

// ...

This is essentially saying:

Hey, I have my string stored in hello, so I am going to call toLowerCase() on hello to give me a copy of hello but with everything in lower case. After that I will assign this value back to hello, effectively replacing the old String which might have had uppercase characters.

Alexandru Doru Grosu
Alexandru Doru Grosu
2,753 Points
Alexandru Doru Grosu
Alexandru Doru Grosu
2,753 Points

You get the error because char(s) and String(s) are two different things. A char, as the name implies, stores a single character. A String (as the name also sort of implies) is a series of characters. Strings are denoted by " " while chars are denoted by ' ';

So for example the String

String hello = "Hello World!";

is made out of the individual char(s)

'H', 'e', 'l', 'l', 'o', 'W', 'o', 'r', 'l', 'd'

The problem with your code is that you are concatenating (by using the + sign) four Strings, and you are trying to store the result of that (which is also a String) into a single character. You are trying to put a bunch of apples into a basket that is only meant to hold one apple essentially.

TL;DR char can store only one character and you are trying to cram a String into it, which is a series of characters.

So to fix your problem, lotsOfStuff has to be of the type String and not char.

ISAIAH S
ISAIAH S
1,409 Points

When I changed:

char lotsOfStuff = number + mood + creature + color;

to:

String lotsOfStuff = number + mood + creature + color;

I got the following error:

Isaiah.java:19: error: no suitable method found for toLowerCase(String)      
Character.toLowerCase(lotsOfStuff);                                          
         ^                                                                   
    method Character.toLowerCase(char) is not applicable                     
      (argument mismatch; String cannot be converted to char)                
    method Character.toLowerCase(int) is not applicable                      
      (argument mismatch; String cannot be converted to int)                 
1 error