I am working on getting a simple calculator working as part of my adventure to learning Object-C and iOS development.
In Object-C using NSString, how does one look for a period in a string?
Based on the comments this is what I got so far.
NSString * tmp = [display text];
NSLog(#"%#", tmp); // Shows the number on the display correctly
int x = [tmp rangeOfString:#"."].location;
NSLog(#"%i", x); // Shows some random signed number
if (x < 0) {
[display setText:[[display text] stringByAppendingFormat:#"."]];
}
It is still not working :(
NSRange is a straight-up struct...
typedef struct _NSRange {
NSUInteger location;
NSUInteger length;
} NSRange;
int x = [#"hello.there.ok" rangeOfString:#"."].location;
printf("x is %d\n",x);
prints 5.
and here is a whole program:
int main(int argc, char *argv[])
{
NSString *ht = #"This is a string";
int r1 = [ht rangeOfString:#"is"].location;
int r2 = [ht rangeOfString:#"is a"].location;
int r3 = [ht rangeOfString:#"isnt"].location;
NSLog(#"r1=%d, r2=%d, r3=%d, that's all\n",r1,r2,r3);
}
which prints:
Program loaded.
run
[Switching to process 21098]
Running…
2011-01-14 20:45:25.192 DELETEME[21098:a0b] r1=2, r2=5, r3=-1, that's all
running this in XCode, Mac OS... should be straightahead!
Related
The functions IOHIDGetAccelerationWithKey and IOHIDSetAccelerationWithKey are deprecated since macOS 10.12, therefore I am trying to implement the same using other IO*-methods.
I have never worked with IOKit, thus, all I can do is google for functions and try to get it to work.
Now I found this: Can't edit IORegistryEntry which has an example of how to change TrackpadThreeFingerSwipe property, however it is using a function which is not defined for me: getEVSHandle. Googling for it reveals only that it should be Found in the MachineSettings framework, however I can't seem to add any "MachineSettings" framework in Xcode 11.
What should I do? Current code is like:
#import <Foundation/Foundation.h>
#import <IOKit/hidsystem/IOHIDLib.h>
int main(int argc, const char * argv[]) {
#autoreleasepool {
NSInteger value = -65536;
CFNumberRef number = CFNumberCreate(kCFAllocatorDefault, kCFNumberNSIntegerType, &value);
CFMutableDictionaryRef propertyDict = CFDictionaryCreateMutable(kCFAllocatorDefault, 1, NULL, NULL);
CFDictionarySetValue(propertyDict, #"HIDMouseAcceleration", number);
io_connect_t connect = getEVSHandle(); // ???
if (!connect)
{
NSLog(#"Unable to get EVS handle");
}
res = IOConnectSetCFProperties(connect, propertyDict);
if (res != KERN_SUCCESS)
{
NSLog(#"Failed to set mouse acceleration (%d)", res);
}
IOObjectRelease(service);
CFRelease(propertyDict);
}
return 0;
}
The following works (tested with Xcode 11.2 / macOS 10.15)
#import <Foundation/Foundation.h>
#import <IOKit/hidsystem/IOHIDLib.h>
int main(int argc, const char * argv[]) {
#autoreleasepool {
io_service_t service = IORegistryEntryFromPath(kIOMasterPortDefault,
kIOServicePlane ":/IOResources/IOHIDSystem");
NSDictionary *parameters = (__bridge NSDictionary *)IORegistryEntryCreateCFProperty(service,
CFSTR(kIOHIDParametersKey), kCFAllocatorDefault, kNilOptions);
NSLog(#"%#", parameters);
NSMutableDictionary *newParameters = [parameters mutableCopy];
newParameters[#"HIDMouseAcceleration"] = #(12345);
kern_return_t result = IORegistryEntrySetCFProperty(service,
CFSTR(kIOHIDParametersKey), (__bridge CFDictionaryRef)newParameters);
NSLog(kIOReturnSuccess == result ? #"Updated" : #"Failed");
IOObjectRelease(service);
}
return 0;
}
I'm trying to create a simple commandline tic-tac-toe game using an NSMutableArray.
Created a class called "Board" with the method "getPosition"
(I'm assuming this is the best way to get a user input)
I'm asking for position, then casting from int to NSUInteger)
#import "Board.h"
#implementation Board
-(void)getPosition;
{
int enteredPosition;
scanf("%i", &enteredPosition);
NSUInteger nsEnteredPosition = (NSUInteger ) enteredPosition;
NSLog(#"Position = %lu", (unsigned long)nsEnteredPosition);
}
#import <Foundation/Foundation.h>
#import "Board.h"
int main(int argc, const char * argv[])
{
#autoreleasepool {
NSString *currentPlayer;
NSMutableArray *gameBoard=[[NSMutableArray alloc] initWithCapacity:9];
for(int i; i<=2; i++)
{
if(i %2)
{
currentPlayer=#"X";
}
else
{
currentPlayer=#"O";
}
NSLog(#"Player %#, select an open spot 1 - 9 on the board", currentPlayer);
Board *currentPosition = [[Board alloc] init];
[currentPosition getPosition];
[gameBoard insertObject:currentPlayer atIndex:currentPosition]; //this is where i have a problem
}
As I understand it atIndex requires an NSUInteger parameter, but I'm receiving the error message:
"Incompatible pointer to integer conversion sending 'Board *_strong"
to parameter of type 'NSUInteger' (aka 'unassigned long')
You're using currentPosition as your index which is a Board object. Perhaps [currentPosition getPosition] is supposed to return an NSUInteger. If so, try rewriting the last portion of your code like this:
Board *theBoard = [[Board alloc] init];
NSUInteger currentPosition = [theBoard getPosition];
[gameBoard insertObject:currentPlayer atIndex:currentPosition]; //this is where i have a problem
I just recently started learning Objective C, when i run the next program i get error
"program received signal: "EXC_BAD_ACCESS"
For the code line
if([*userChoice isEqualToString:#"yes"])
The full code is:
void initGame (void);
void restartGame(void);
void toGoOn(char *playerChoice);
int guess=-1;
int from=-1;
int to=-1;
bool playStatus=true;
bool gameStatus=true;
int answer=-1;
NSString *userChoice[10];
//if true the game is on
int main (int argc, const char * argv[])
{
#autoreleasepool {
GuessManager *game=GUESS;
NSLog(#"Hello, lets play");
NSLog(#"Please provide a positive range in which you would like to play");
do{
initGame();
[game setnumberToGuess:from :to];
do {
printf("Make you guess:");
scanf("%d", &guess);
[game setUserGuess:guess];
[game checkUserGuess];
if([game getDidIgetIt])
{
playStatus=false;
}
else
{
playStatus=true;
}
} while (playStatus);
restartGame();
}while(gameStatus);
printf("Thanks For Playing PanGogi Games! GoodBye");
}
return 0;
}
void initGame (void)
{
printf("from:");
scanf("%d",&from);
printf("to:");
scanf("%d",&to);
}
void restartGame(void)
{
printf("Would you like to continue?(yes/no)");
scanf("%s",&userChoice);
//scanf("%d",&answer);
// if(answer==1)
if([*userChoice isEqualToString:#"yes"])
{
gameStatus=true;
}
else
{
gameStatus=false;
}
}
I understand that its related to the NSString variable userChoice and how its used in
the if, but what i cant find is what am i doing wrong.
Please help :)
You have 3 errors in the code
1) I think you are getting confused with NSString and C style char array... You just need to use single NSString object to save multi character data..
NSString *userChoice;
2) Since you want to input data using scanf, you need a C style character array. scanf won't work with NSString types.
char tempArray[10];
int count = scanf("%s",&tempArray);
userChoice = [NSString stringWithBytes:tempArray length:count encoding: NSUTF8StringEncoding];
3) Now you can use NSString directly.. No need for pointer like syntax
if( [userChoice isEqualToString: #"yes"]){
.....
.....
}
You're using NSString as if it was char. It's not. It's a class that represents a string.
The scanf function is a C function and needs a char array, not an NSString.
char str[80];
scanf("%s", &str);
You can initialize an NSString object with a char array like this:
NSString *userChoice = [NSString stringWithCString:str encoding:NSASCIIEncoding];
And compare like this:
if ([userChoice isEqualToString:#"yes"]) {
...
} else {
...
}
Does anyone know of an existing way to change the order of an existing NSString or NSMutableString's characters? I have a workaround in mind anyway but it would be great if there was an existing method for it.
For example, given the string #"HORSE", a method which would return #"ORSEH", #"SORHE", #"ROHES", etc?
Consider this code:
.h File:
#interface NSString (Scrambling)
+ (NSString *)scrambleString:(NSString *)toScramble;
#end
.m File:
#implementation NSString (Scrambling)
+ (NSString *)scrambleString:(NSString *)toScramble {
for (int i = 0; i < [toScramble length] * 15; i ++) {
int pos = arc4random() % [toScramble length];
int pos2 = arc4random() % ([toScramble length] - 1);
char ch = [toScramble characterAtIndex:pos];
NSString *before = [toScramble substringToIndex:pos];
NSString *after = [toScramble substringFromIndex:pos + 1];
NSString *temp = [before stringByAppendingString:after];
before = [temp substringToIndex:pos2];
after = [temp substringFromIndex:pos2];
toScramble = [before stringByAppendingFormat:#"%c%#", ch, after];
}
return toScramble;
}
#end
Not the most beautiful code or execution, but gets the job done. There's probably a (const char *) way to do this, but this works fine for me. A quick test shows a 0.001021 second length for execution on my Mac.
Usage:
NSString *scrambled = [NSString scrambleString:otherString];
Code adapted from another language / pseudocode
You can use Durstenfeld's variation of the Fisher-Yates Shuffle.
For a very long string, you could save a lot of CPU time and allocations by copying the unichars to a unichar buffer, then performing the transform using a c or c++ approach to swap characters. Note that the UTF8String is not the buffer you want to take, nor should you mutate it. Then create (or set) a new NSString from the shuffled buffer.
More info on the Fisher Yates algo and C and C++ implementations can be found here.
I'm trying to call a simple tutorial C function from Objective-C and I can't figure out how to split up the arguments being passed, which is two strings.
int cFunction(int argc, char **argv)
{
int i;
printf("argc = %d\n", argc);
for (i = 0; i < argc; i++) {
printf("argv[%d] = \"%s\"\n", i, argv[i]);
}
return 0;
}
I've tried cFunction(3, "string1 string2"), cFunction(3, "string1", "string2"), and cFunction(3, args), with args being an NSArray composed of [textField1 stringValue] and [textField2 stringValue]
I get EXC_BAD_ACCESS when trying to printf argv[i]. I've also tried passing 2 as the value of argc.
How should this be called? Thanks
In this function parameter list, argv is a pointer to a C string array (char **).
Using the Objective-C NSString or NSArray type isn't possible with this function, First, convert each string using -(const char *)cStringUsingEncoding:(NSStringEncoding)encoding;, and store them into a C array of strings.
// myString is "arg1"
// mySecondString is "arg2"
char *cString = [myString
cStringUsingEncoding:NSUTF8StringEncoding];
char *cSecondString = [mySecondString
cStringUsingEncoding:NSUTF8StringEncoding];
char *myStrings[2] = { cString, cSecondString };
int returnCode = cFunction(2, myStrings);
This should work.