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To use method from the main method java [closed]

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This question is pretty specific for my problem, that is why I am creating a new question. The second method in this program is supposed to make a row of the number 1 2 3 4 5 6 7 8 9 10. The only problem I am having is that I don't know how to print this out in the main method.
public class Uppgift1_6a
{
public static void main(String[] args)
{
for(int k = 0; k < 10; k++)
{
int tal = Numberline(k);
System.out.print(tal);
}
}
public static int Numberline(int tal1)
{
int tal = 1;
for(int i = 1; i < 11; i++)
{
tal = tal1 + i;
}
return tal;
}
}
Right now it prints out all the number from 11 to 19. And if I change it, it only prints out either 10 or 11.

Look closely at the code:
public static int Numberline(int tal1)
{
int tal = 1;
for (int i = 1; i < 11; i++)
{
tal = tal1 + i;
}
return tal;
}
The for loop literally does absolutely nothing - you're only returning the final result. The final result is always exactly equal to tal1 + 10; again, what the for loop did up this point makes no difference. (I'd encourage you to step through the code with a debugger to convince yourself of that fact).
If you want it to print out the values as you're going through the for loop, you need to do something like:
for (int i = 1; i < 11; i++)
{
// You may need to modify this line too, depending on what values you want printed
tal = tal1 + i;
// Print the value here
System.out.print(tal);
}
because the way you've written it it'll only print out the final value of tal (the one you returned).

How can i count how many times the keywords user enter is the used in the essay. its doesn't check on the entire keyword [closed]

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public static int keywordsChecker(String essay,String key) {
int count = 1;
String[] k=key.split(",");
for (int i = 0; i < k.length-1; i++) {
if (essay.contains(k[i])) {
count++;
}
}
return count;
}

To take into account that each keyword searched for may occur more than once, and to count such occurrences, you may use this inside your for loop:
int indexOfOccurrence = essay.indexOf(k[i]);
while (indexOfOccurrence > -1) {
count++;
indexOfOccurrence = essay.indexOf(k[i], indexOfOccurrence + 1);
}
There are a couple of other issues in your code: I believe you need to initialize count to 0 (not 1). And to count also the last keyword in key your for loop should be for (int i = 0; i < k.length; i++) (without subtracting 1 from k.length). If you want, using <= would also work: for (int i = 0; i <= k.length-1; i++), but this is non-standard, so I would not recommend it.

Better Selection Sort in Java [closed]

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Firstly, can you tell me which piece of code is better of selection sort? Then if you know better ways for selection sort, can you please share?
Note: Please inspect the second code closer because it is more complex than it looks.
class SelectionSort {
public static void selectionSort(double[] list) {
for (int i = 0; i < list.length - 1; i++) {
double currentMin = list[i];
int currentMinIndex = i;
for (int j = i + 1; j < list.length; j++) {
if (currentMin > list[j]) {
currentMin = list[j];
currentMinIndex = j;
}
}
if (currentMinIndex != i) {
list[currentMinIndex] = list[i];
list[i] = currentMin;
}
}
}
}
.
class SelectionSort {
public static double[] selectionSort(double[] array) {
for (int i = 0; i < array.length; i++) {
for (int j = 0; j < i; j++) {
if (array[j] > array[i]) {
double temp = array[j];
array[j] = array[i];
array[i] = temp;
}
}
}
}
}

Both methods will solve your problem but the second one it's clearly and I think it will be faster. Why? Because it has to make less actions to complete the problem: in the first one you have 2 loops (like in the second one), but also it has to make 2 ifs vs 1 if in the second one. I'm not really secure about that but, if the program have to make less actions, it will be faster (just an assumption).
Also, I think it will be faster because in the first one, you through all the j elements, some of them unnecesary (you have to make an extra if), and in the second one you just go through the elements that you need so it is more efficient too.
So, in conclusion, I think the best practice that you have to use it's the second one.
I expect it will helps you a bit!

Performance wise, both are similar, O(n2). The second code is a bit cleaner though.

Java loop can't iterate down string length [closed]

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Closed 8 years ago.
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Here is some basic code:
public static void main(String[] args) {
String string = "Hello!";
System.out.println("First loop.");
for (int i = 0; i < string.length(); i++) {
System.out.println("g");
}
System.out.println("Second loop.");
for (int i = (string.length() - 1); i <= 0; i--) {
System.out.println("g");
}
}
For some reason, the program won't go through the second loop at all. This is somewhat strange. Can you explain this, and how to fix it?

Your second loop should be looping backwards, while the index is still greater than or equal to zero, not less than or equal to zero. With <= 0, i is greater than zero on the first evaluation and the loop never runs.
Try:
for (int i = (string.length() - 1); i >= 0; i--) {

Change the for condition,the i is initial with value greater than 0 (length-1) and there is condition i <= 0 which is true in case length is equal to 1.But the length of string is 6 so change the condition as below :
for (int i = (string.length() - 1); i >= 0; i--) {
System.out.println("g");
}

Your problem is the condition in the second for loop
i <= 0
never happens. I don't understand why you would want to check that.

Difference between prefix and postfix operators in different situations [closed]

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I have gone through all the questions in this forum that are corresponding to this topic, and I felt to raise a different question as this question is not answered clearly. Here is my scenario:
I have this class Test1:
public class Test1 {
public static void main(String args[]) {
int i=0, j=2;
do {
i= i+1;
j--;
} while(j>0);
System.out.println(i);
}
}
Now this is my question:
a) If I replace the increment operation of 'i= i+1' with ++i, I get the desired output as
1
2
But if I replace the increment operation of 'i= i+1' with i++, I get the desired output as
0
0
I do understand the difference of using prefix and postfix operators in for loop, but why is the value not getting incremented at all in do-while loop?

Using i = i++; will never change i value.
Use just:
i++;
Why? because:
i = i++;
is similar to doing something like this:
temp = i; // temp is 0.
i = i+1; // increment i
i = temp; // assign temp (which is 0) to i.
Take a look at a similar post-increament question and even another one.

++i
This will increment i, then return it.
i++
This will return i, then increment it.
Example
Here is a link to an ideone example of this.
int i = 5;
System.out.println(i++);
// Outputs 5
int j = 5;
System.out.println(++j);
// Outputs 6.

x = i++; is a shortcut for x = i; i = i + 1;
x = ++i; is a shortcut for i = i + 1; x = i;
that's it.

Actually in your sample, there should be no difference between i++ and ++i, if you replace i = i+1 by one of two. Chris noted the difference correctly, I'll just add a sample, where this is important:
int i = 0;
method(i++);
Will call method with the original value of 0 and increment i afterwords. In method, however, you'll see the original value 0.
int i = 0;
method(++i);
Will increment i and then call method. So in method you'll get the value of 1. That does not change the fact that after method, i has the value 1 in both cases.
Others have noted correctly that
i = ++i;
and
i = i++;
are different things actually!