I have a bit of code here and what I want to happen is that every time it is triggered the integer 'lives' goes down by one. Here is my code.
if (match == NO)
{
self.wrongLetters = [self.wrongLetters stringByReplacingOccurrencesOfString:letterToCheck withString:#""];
self.wrongLetters = [self.wrongLetters stringByAppendingString:letterToCheck];
while (!lives == 0)
{
lives--;
self.HangmanStatus.text = [[NSString alloc] initWithFormat:#"Lives Left: %d", lives ];
}
}
But instead of going down by one it goes down all the way to 0.
Am I triggering it incorrectly?
Advice would be awesome, Thanks
You want:
while (lives != 0) {
}
Another option would be:
while (lives > 0) {
}
This will guard against lives being negative somehow.
But if you just want lives to go down once, change the while to if.
if (lives > 0) {
}
The expression !lives == 0 negates the value of lives then checks to see if that value is equal to 0. Not what you want.
while(!(lives == 0)) should fix your issue.
Or, better yet, while(lives != 0)
Because of the order in which operations are applied, while(!lives == 0) is actually applying the ! operator to lives, which is not what you want to do.
Lives is inside of a while loop with the condition "while lives is not equal to 0, decrement lives." Therefore, the statements in the condition are run until the condition is satisfied -- until lives is equal to zero.
Related
in my code I have the following if statement:
if (a.count >= 2) {
t2 = array[b % a.count];
array[0] = t2;
}
I have another if statement that goes like the first. What I want it to do is if a <= 0 then goto a certain line, or skip over certain parts of code. How would I do this? I was thinking something along the lines of
if (a.count <= 0) {
goto line 96
}
This wouldn't work, the syntax is wrong, but how would I do this?
Goto statements are generally considered bad programming and excessive utilization of them can lead to code that is hard to maintain and debug.
That said, if/else/else if provide all the functionality you need.
I recommend putting the code you need to run inside that if statement in a separate method and then calling it from the if statement.
if (a.count <= 0) {
nameOfNewMethod();
}
//somewhere else
- (void) nameOfNewMethod {
//code here
}
Put the lines of code you want to "goto" in a function (or if appropriate, a block) and call the function (or block). If there are lines of code you want to skip, you can always return early out of a function, or use an else block?
There is in fact a goto command in Objective-C. To utilize it, you have to create a label, ex:
marker:
and jump to it like so within the same method:
goto marker;
But you can't declare any variables between those two commands. All the variables have to be created before the jump so that they still exist after.
Here's an example of how to use goto:
int x = 0;
if (a.count <= 0) {
goto marker;
}
x = 5;
marker:; // <-- semi-colon indicates the label is followed by an empty statement, thus allowing for immediate variable declaration
int y = x + 7;
In that case, if a.count <= 0, y == 7, else y == 12.
I have a total of 6 booleans and the only thing separating them is a number. They're named checker0 though 5.
So checker0, checker1, checker2, checker3, checker4 and checker5.
All of these grants or denies access to certain parts of the app wether the bool is true or false.
I then have a randomiser using:
randomQuestionNumber = arc4random_uniform(5);
So say we get number 3, checker3 = true;
But my question now is would it be possible to set this one to true without having to go thru if statements.
My idea was to implement the way you print a int to say the NSLog using the %d.
NSLog(#"The number is: %d", randomQuestionNumber);
So something like:
checker%d, randomQuestionNumber = true.
Would something like that be possible? So i won't have to do like this:
if (randomQuestionNumber == 0) {
checker0 = true;
}
else if (randomQuestionNumber == 1)
{
checker1 = true;
}
Thanks you very much! :)
Every time you find yourself in a situation when you name three or more variables checkerN you know with a high degree of probability that you've missed a place in code where you should have declared an array. This becomes especially apparent when you need to choose one of N based on an integer index.
The best solution would be to change the declaration to checker[6], and using an index instead of changing the name. If this is not possible for some reason, you could still make an array of pointers, and use it to make modifications to your values, like this:
BOOL *ptrChecker[] = {&checker0, &checker1, &checker2, ...};
...
*ptrChecker[randomQuestionNumber] = true;
I am developing an app where the user receives an overall score and are judged from that score and given a title. However, with the code I am using, the end result is always the same, no matter what score the subject gets. I dont know if this a math problem or a code problem, as it always comes up with the first option: You have no SWAG whatsoever...
if (totalScore<24) {
describe.text = #"You have no SWAG whatsoever...";
}
else if (25<totalScore<49) {
describe.text = #"You seem to be new to SWAG.";
}
else if (50<totalScore<74) {
describe.text = #"You have a bit of SWAG, not enough though.";
}
else if (75<totalScore<99) {
describe.text = #"You definately have SWAG!";
}
else if (totalScore == 100) {
describe.text = #"You are a GOD of SWAG.";
}
else if (25<totalScore<49) {
should be:
else if (25<totalScore && totalScore<49) {
The way you wrote it is parsed as if you'd written:
else if ((25<totalScore) < 49) {
25<totalScore will be either 1 or 0 depending on whether it's true or false. Either way, it's less than 49.
Also, all your comparisons should be <= rather than <. Otherwise, you're excluding all the boundary values.
building if in this way
if (25<totalScore<49) {...}
is risky.In reality you do something like
25<totalScore -> YES/NO (values will be casted from BOOL to int as 1/0)
and then you will do
0/1 < 49 which will be always true.
so in total your if is wrong.
Your first line of code looks right from what you have displayed so far? You need to output what total score is. You are maybe not setting it before running your code?
Failing that, are you sure its compiling properly? You need to use && in your subsequent if statements.
Also, you need to use <=, because at the moment, if the score is 24 it wont work.
I'm trying to write code that detects if an integer is greater than another integer. Is this possible?
Here is what i've done so far.
if (NumCorrect >> NumWrong) {
btnCool.title = #"Awww";
}
else {
btnCool.title = #"Cool!";
}
All its doing is going to the else
EDIT:
NSString *numCorrect = [NSString stringWithFormat:#"%d",NumCorrect];
NSString *numWrong = [NSString stringWithFormat:#"%d", NumWrong];
lblWrong.text = numWrong;
lblCorrect.text = numCorrect;
if (NumCorrect > NumWrong) {
btnCool.title = #"Awww";
} else {
btnCool.title = #"Cool!";
}
Use single >
if (NumCorrect > NumWrong) {
btnCool.title = #"Awww";
} else {
btnCool.title = #"Cool!";
}
Double >> is a bit shift operation. You shift every bit in the binary representation of your variable NumCorrect NumWrong amount of bytes to the right. In almost all cases this will return in a number other then 0, which will then treated as a false value and thus the else block is executed.
Almost perfect - just take off one of those >'s. >> and << are for "bit-shifting", a weird hold-over from the earliest days of programming. You're not gonna use them much. What you really want is > and <, which is for testing if numbers are greater than each other or less than each other.
In addition, you may remember from math class that ≥ and ≤ (greater-than-or-equal-to and less-than-or-equal-to) are useful operations as well. Because there's no symbols for those on most keyboards, however, C and Xcode use >= and <= instead.
Finally, you may already know this, but to check if two numbers are exactly equal to each other you can use == (because = is used for setting the contents of variables).
Hope that's helpful!
I want to make a selection before apply one of two animations,
what I thought is: make a Point one, if my myImageView is at the Point one, then apply animationNo1, else apply animationNo2, but I got this:"used struct type value where scalar is required", at line if (myImageView.layer.position = one)
What I do? how can I fix this?
Does anyone know exactly what makes the problem happen?
CGPoint one = CGPointMake(myImageView.layer.position.x, 100);
if (myImageView.layer.position = one)
{
animationNo1
}
else
{
animationNo2
}
First of all, your if-statement will not do what you think. If you want to compare something you have to use == (ie 2 =)
and you can't compare CGPoints like this.
use
if (CGPointEqualToPoint(one, self.view.layer.position))
if (myImageView.layer.position = one) { animationNo1 }
should be
if (CGPointIsEqualToPoint(myImageView.layer.position, one)) { animationNo1 }
You used a single = meaning assignment, rather than a == for comparison. But the == wouldn't do what you wanted here anyway.
You are passing a struct (int this case position) instead of a scalar. To do what you want you need to use CGPointIsEqualToPoint:
if (CGPointEqualToPoint(one, self.view.layer.position))
Full code with corrections:
CGPoint one = CGPointMake(myImageView.layer.position.x, 100);
if (CGPointEqualToPoint(one, self.view.layer.position))
{
animationNo1
}
else
{
animationNo2
}
Also, as others have pointed out: Be careful about = vs ==. They are different. In this case you don't use == for comparison fortunately, but if you use = for other stuff it will make it true instead of checking to see if it is true.