Working through java, a beginners guide 5th ed one of the examples:
[source lang="java"]public class forDemo {
// Demonstrates the for loop
public static void main(String[] args) {
// TODO Auto-generated method stub
int count;
for (count = 0; count < 5; count = count + 1);
System.out.println( "This is count: " + count);
System.out.println( "Done!");
}
}[/source]
The author goes on to say that the example is not good programming and that you will not see programmers use that example, you would probably se this instead: count++.
But when I run it with the latter:
[source lang="java"]
public class forDemo {
// Demonstrates the for loop
public static void main(String[] args) {
// TODO Auto-generated method stub
int count;
for (count = 0; count < 5; count = count++);
System.out.println( "This is count: " + count);
System.out.println( "Done!");
}
}
[/source]
it runs "this is count: 0 infinitely
thanks for any help.
count++ & infinite loop
It's just count++, not count=count++. It's not better programming per se, just shorter. I don't use it the way you have, but if I recall correctly the return value of count++ is count, whereas the return value of ++count is count+1.
It makes more sense as below:
[source lang="java"]int count = 0;
count++; // count is 1 after this
++count; // count is 2 after this
int a = count++; // a is 2, count is 3 after this
int b = ++count; // b is 4, count is 4 after this
[/source]
It makes more sense as below:
[source lang="java"]int count = 0;
count++; // count is 1 after this
++count; // count is 2 after this
int a = count++; // a is 2, count is 3 after this
int b = ++count; // b is 4, count is 4 after this
[/source]
To be honest, I'm not sure why count = count++; isn't working (even though you should only write it as count++). It looks like it could be language specific behaviour
What should happen is count is assigned the value of count, then it is incremented by 1.
count = count++ //1
count = count++ //2
I'm interested as to why this isn't true in java
What should happen is count is assigned the value of count, then it is incremented by 1.
count = count++ //1
count = count++ //2
I'm interested as to why this isn't true in java
Author
When I write:
[source lang="java"]for (count = 0; count < 5; count++);[/source]
it gives me: [size="2"]This is count: 5
[size="2"]From what the author says it's suppose to display the exact loop as the first example:
[source lang="java"] for (count = 0; count < 5; count = count +1);[/source]
thanks again.
[source lang="java"]for (count = 0; count < 5; count++);[/source]
it gives me: [size="2"]This is count: 5
[size="2"]From what the author says it's suppose to display the exact loop as the first example:
[source lang="java"] for (count = 0; count < 5; count = count +1);[/source]
thanks again.
Another thing, if you put a semicolon after a loop statement it turns the loop into a empty loop (since the semicolon by itself is simply the null statement). To fix this problem you need to get rid of the semicolon after the for statement (but only after the for statement).
Author
Um... nevermind. I guess this is why you should check the code first!
[color="#006699"]for [color="#000000"](count = [color="#009900"]0[color="#000000"]; count < [color="#009900"]5[color="#000000"]; count = count + [color="#009900"]1[color="#000000"]); <<<<<semicolon - that's why it didn't work. sorry guys.
So would that be more relevant, er... a better writing of that code? I just don't want to get into the habit of writing code people may frown upon.
[color="#006699"]for [color="#000000"](count = [color="#009900"]0[color="#000000"]; count < [color="#009900"]5[color="#000000"]; count = count + [color="#009900"]1[color="#000000"]); <<<<<semicolon - that's why it didn't work. sorry guys.
It's just count++, not count=count++. It's not better programming per se, just shorter. I don't use it the way you have, but if I recall correctly the return value of count++ is count, whereas the return value of ++count is count+1.
It makes more sense as below:
[source lang="java"]int count = 0;
count++; // count is 1 after this
++count; // count is 2 after this
int a = count++; // a is 2, count is 3 after this
int b = ++count; // b is 4, count is 4 after this
[/source]
So would that be more relevant, er... a better writing of that code? I just don't want to get into the habit of writing code people may frown upon.
Author
Another thing, if you put a semicolon after a loop statement it turns the loop into a empty loop (since the semicolon by itself is simply the null statement). To fix this problem you need to get rid of the semicolon after the for statement (but only after the for statement).
Yeah I just got that as you posted. Thanks Ruler
The traditional way is as stated:
for (count = 0; count < 5; count++)
I was just pointing out that it won't make your code in any way faster or better, just more concise.
for (count = 0; count < 5; count++)
I was just pointing out that it won't make your code in any way faster or better, just more concise.
The result of the expression 'count++' is the value of count before incrementing it (0). So a repeated 'count = count++' is basically the same as saying 'count = 0'.
'count = ++count' would give the expected result, although there is no point in assigning count's value to itself.
'count = ++count' would give the expected result, although there is no point in assigning count's value to itself.
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