Java For loop to print out numbers in order

[ByBoz]

Hi, I'm trying to write a code with for-loop to get numbers in order. For example 3,4,5,6 or -1,0,1,2,3. This is what I have come up with this far.

public static void runLoop(int start, int end){

    
    for (start <= end; start++){
        System.out.print(start);
    
    }
}

 

[menator01]

public class test {
    public static void main(String[] args) {
        for (int i = -3; i < 4; i++) {
            System.out.println(i);
        }
    }
}

output

-3
-2
-1
0
1
2
3

 

[Deleted member 2829]

CODE=java]public static void runLoop(int start, int end){
for (start <= end; start++){
System.out.print(start);
}
}
[/CODE]

I guess you did not try to compile that code ? Here's what you would have seen then :

D:\java>javac runLoop.java
runLoop.java:1: error: class, interface, enum, or record expected
public static void runLoop(int start, int end){
^
runLoop.java:4: error: class, interface, enum, or record expected
for (start <= end; start++){
^
runLoop.java:7: error: class, interface, enum, or record expected
}
^
3 errors

If you are not aware that Java always wants a class definition, please read up on the basics of Java. So with a class definition added:

public class test{
    public static void runLoop(int start, int end){
        for (start <= end; start++){
            System.out.print(start);
        }
    }
}

the compiler now says

D:\java>javac test.java
test.java:6: error: not a statement
for (start <= end; start++){
^
test.java:6: error: ';' expected
for (start <= end; start++){
^
2 errors

so you need to read up on how to write a for loop, and what the 3 different parts mean. The correct syntax here is for (; start <= end; start++) Note the empty start condition. There actually is no start condition here, but you have to obey the syntax nonetheless. Java is very pedantic.

So with that added, your code compiles clean. Now of course you'll somehow want to call this method (nobody's going to do that for you), so you best add a main() method. If you're not aware Java programs need a main() method, read up on the basics again. Finally you'll see that it prints everything on one line, so you'd better use println rather than print.

All of these points are of course already implicitly made clear by the code @menator01 kindly provided 😉