High-Low Guessing Game

The program is asking you to guess a number between 1-100 and if you guessed too low it says that in Swedish and the same goes for if it's too high and if it's the correct answer it says congratz you guessed right in Swedish.

public class Kidsprogram {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
Random rand = new Random();
int number = rand.nextInt(100) + 1;
System.out.println("Gissa på ett nr mellan 1 och 100");
for (int i = 1; i > -1; i++)
{
int guess;
guess = input.nextInt();
if (guess < number)
{
}
else if(guess > number)
{
}
else if(guess == number)
{
System.out.println("Antal gissningar: " + i);
break;
}
}
}
}


Scanner is an auto-closable resource, an it should be closed. Your code is probably showing a warning for that in your IDE. The following should help:

try (Scanner scanner = new Scanner(System.in)) {
}


While the close on the System.in is often ignored, when putting a Scanner on it, you should do it to remove the warnings.

Function extraction is a good thing, and when dealing whith human interaction, you should be defensive about handling user input. What happens if the user types "foo", instead of a number?

A method like:

public static int readInt(Scanner scanner) {
while (!scanner.hasNextInt()) {
System.out.println("Det är inget tal. Ange ett värde (1-100):");
scanner.next();
}
return scanner.nextInt();
}


will loop until there is a valid input.

Your main mentod is still doing too much, though, your should probably extract the random number too. Consider:

private static int randomInt(int from, int to) {
Random rand = new Random();
return rand.nextInt(to - from + 1) + from;
}


Then you can call:

int number = randomInt(1, 100);


Finally, you can outsource the whole thing to:

public static void main(String[] args) {
try (Scanner scanner = new Scanner(System.in)) {
System.out.println("Guess!");
int turns = countTurns(scanner, randomInt(1, 100));
System.out.println("Antal gissningar: " + turns);
}
}


if you have a countTurns method:

private static int countTurns(Scanner scanner, int number) {
int turn = 0;

while (true) {
turn++;
if (guess < number) {
} else if (guess > number) {
} else {
return turn;
}
}
}

public static int readInt(Scanner scanner) {
while (!scanner.hasNextInt()) {
System.out.println("Det är inget tal. Ange ett värde (1-100):");
scanner.next();
}
return scanner.nextInt();
}

private static int randomInt(int from, int to) {
Random rand = new Random();
return rand.nextInt(to - from + 1) + from;
}

public static void main(String[] args) {
try (Scanner scanner = new Scanner(System.in)) {
System.out.println("Guess!");
int turns = countTurns(scanner, randomInt(1, 100));
System.out.println("Antal gissningar: " + turns);
}
}


Since the end condition of the loop is always true, you can just omit it:

    for (int i = 1; ; i++)


The condition in the final else if(guess == number) is always true, so you can use simply else.

There's no need to separate the declaration and initialization of the guess variable, you can do int guess = input.nextInt() which is shorter.

The convention in Java is to put opening braces on the same line as the statement, like this:

    for (int i = 1; ; i++) {
int guess = input.nextInt();
if (guess < number) {
} else if(guess > number) {
} else {
System.out.println("Antal gissningar: " + i);
break;
}
}

1. Put Scanner scanner = new Scanner(System.in) in a try block to safely close the input stream upon termination.

2. Consider declaring int guess = 0 outside of the loop, and use that for the end condition of the for loop:

int guess = 0;
for (int i = 1; guess != number; i++) {
...
}

3. Since the output for a wrong guess is largely similar, you can also consider experimenting with the ternary operator to determine the String you want to display. The minor downside to this is that implicitly, you have a nested if statement instead of the one if-else-if-else flow now.

Putting them together:

    int guess = 0;
for (int i = 1; guess != number; i++) {
guess = input.nextInt();
if (guess != number) {
System.out.println("Du gissade för " + (guess < number ? "lågt" : "högt"));
} else {
System.out.println("Antal gissningar: " + i);

Scanner should be put in a try block, as others have said, to make sure it is closed.
try(Scanner scanner = new Scanner(System.in)) { ... }

3. Loop Your for loop is just creating an infinite loop. Assuming that's what you want it to do (which, from the code, it looks like you do), you should just use a much simpler while(true) loop, with exactly the same code inside it.