first year project

blocparty

im in first year and i cant manage to find the problem in the programme i have written. the basic concept is to write a programme to allow the user to play a number guessing game.

import java.io.*;

class guess

{
public static void main (String[] args) throws IOException
{
BufferedReader stdin =
new BufferedReader ( new InputStreamReader( System.in ) );

String InData;

int guess;
final double answer = 61;


System.out.println("Enter your guess (1-100):");
InData = stdin.readLine();
guess = Integer.parseInt (InData);

if ( guess = 61 )

{
System.out.println("Congragulations you have guessed correctly!");
}
else if ( guess != 61 )
{

System.out.println("You have not guessed correctly!");
}
if ( guess < 61 )
{

System.out.println("The answer is higher!");
}
else if ( guess >= 61 )
{

System.out.println("The answer is lower!");

}
}




if anyone could help me find the problem it would be much appreciated

its saying that a boolean is required on the first line of the if statement

bringitdown

if ( guess = 61 ) .... have a good look at this line.

PS: put constants on the left hand side if at all possible to avoid this error.

timeout

Take a good look at the line

if ( guess = 61 )

Also change the name of your class (guess) or the integer value (guess) to avoid confussion, I had to look at it twice.

blocparty

what are constants? have you spotted the mistake? and trynig to make me spot it?

pH

They're trying to say in java there's a difference between = (assignment) and == (equality). You should be using ==

bringitdown

61 is a constant for example.

I have spotted a mistake and am trying to help you spot it rather than give you the answer straight out.

Hint: Change it to if(61 = guess)

blocparty

ok problem solved. thanks a million guys and thanks for the little pointers.


now one final question:

how do i get the programme to run itself allowing the user to enter a guess one after another without having to type in: java guessGame each time after a guess?

ps i changed the name of the class to guessGame

Mutant_Fruit

Stick in a loop (like a while loop) and let it keep looping until the press 'q' (for quit) or whatever.

In the loop you should check for their next guess etc etc

blocparty

Mutant_Fruit wrote:

In the loop you should check for their next guess etc etc

what do you mean by check their next guess?

timeout

No need to have that press q to quit thing just let the program run till you guess the right answer, much more fun

He means that you need to check for the next guess they make if they don't get it right. Also if you do decide to put the press q to quit thing in you will then have to be checking for both characters (i.e the q) and integer( i.e. the guess)

pH

It's also a great chance to learn to use java classes and methods, how to structure a program and why you don't just stick all your code in the main method

blocparty

well programme is now complete managed to get the loop working myself so im happ with that. i just put in a line: while ( guess != answer)

now i have to write an advanced version of the game. limited to 5 guesses.

id like to put in lines so if the user enters a number outside 1 and 100 it will correct them and say please enter a number between 1 and 100. and another line that will make sure they dont guess the same number twice.

but this will prob just confuse the whole thing

Vegeta

to limit the program to only allow the user to guess 5 times you will need something to count the number of guesses, so everytime a user enters a value make count 1 bigger,count should be initialised to zero everytime the program begins from the start.

Sounds like you'll have to use a nested statement if you know what that is. if count is less than 5 and and then if guess != answer.

blocparty

ya im in the process of doing that now

blocparty

it says that the variable count might not have been initialized.

not sure whats wrong it looks right to me


while ( count <= limit)

{
count = 0;


if ( guess < 57 )
{
System.out.println("The answer is higher!");
}

else if ( guess >= 57 )

{
System.out.println("The answer is lower!");
}


count = count +1;

pH

You need to initialise count to zero before the while

int count = 0;
while (count++ <= limit) {
 ...
}

or use a for

for (int count=0;count<= limit; count++) {
 ...
}

Tobias Greeshman

try initialising the count variable outside of the loop, and use count++ instead of count = count + 1. Your missing a closing brace for the loop as well.

blocparty

ya forgot that you had to initialize outside the loop. i have a closing brace just didnt copy and paste it by mistake.

nice one lads

themole

you should also not us the number 62 directly,

you should be using answer everywhere 61 is used so that to change the answer you only have to change the value of the answer variable.

ie
if ( guess < 61 )
{

System.out.println("The answer is higher!");
}

should be
if ( guess < answer )
{

System.out.println("The answer is higher!");
}

timeout

Well to make it a proper guessing game, you should randimise the answer. It will pick a random number between 1-100 automatically when the program starts. But that is a minor detail to be added when the program is working for a set value.

Hobbes

pH wrote:

You need to initialise count to zero before the while

A gotcha for future reference. If the variable is not within a method it is automatically initialised to its default value.

eg.

class MyClass {

 int count;  // This will default to zero.

 myMethod() { 
   int secondCount; // This will not compile. Needs a value. 
   int thirdCount = 0; // This is what you should do here. 
 }

} 

Mutant_Fruit

Its good practice to initialise all your values. It can help stop stupid/hard-to-find bugs from cropping up later on. Program in C and you'll know what i mean.

Hobbes

Mutant_Fruit wrote:

Its good practice to initialise all your values. It can help stop stupid/hard-to-find bugs from cropping up later on. Program in C and you'll know what i mean.

True. Although the compiler will give a warning that a variable might not be initialised before being used.

dionsiseire

might be an idea to look up the Rand function

randomise the answer and make it a bit more useful to yourself