Cocoa Touch - Comparing Ints - cocoa-touch

Question

I have a maybe simple problem. I am going to generate 3 random numbers ranging from 0 to 2 and I want to determine if there are any duplicates.
Any ideas?

Answer 1

if (num1 == num2) {
}
else if (num1 == num3) {
}
else if (num2 == num3) {
}
else {
//There are no dups.
}
Checks if there is a duplicate.
if (num1 == num2) {
counter++;
}
if (num1 == num3) {
counter++;
}
if (num2 == num3) {
counter++;
}
This finds how many duplicates there are (for an added bonus).
EDIT:
For x amount of numbers you might want to do this (using 10 as my example amount of ints):
int counter = 0;
int i[10] = {
1, 2, 3, 4, 5, 6, 7, 8, 9, 10
};
for (int g = 0; g < 10; g++)
{
for (int j = g+1; j < 10; j++)
{
if(i[g] == i[j])
{
counter++;
printf(#"%d\n", counter);
//If this if statement is true then there is a dup... In this case none are found.
}
}
}

Answer 2

How about this?
NSArray *randomNumbers = [[NSArray alloc] initWithObjects:#"0",#"1",#"1",#"2",nil];
NSMutableDictionary *occurenceDict = [[NSMutableDictionary alloc] init];
for (NSString *number in randomNumbers)
{
if ([occurenceDict objectForKey:number] == nil) {
[occurenceDict setValue:[NSNumber numberWithInt:[number intValue]] forKey:number];
int occOfNum = 0;
for (int i = 0; i < [randomNumbers count]; i++) {
NSString *currentNumber = [randomNumbers objectAtIndex:i];
if ([currentNumber compare:number] == NSOrderedSame) {
occOfNum++;
}
}
[occurenceDict setValue:[NSNumber numberWithInt:occOfNum] forKey:number];
}
}
for (NSString *key in occurenceDict) {
NSString *occurrences = [occurenceDict objectForKey:key];
NSLog(#"Number %d is contained %d times", [key intValue], [occurrences intValue]);
}
[randomNumbers release];
[occurenceDict release];
Output:
Number 0 is contained 1 times
Number 1 is contained 2 times
Number 2 is contained 1 times
Edit: Incase you want to know how this works, here is the same version but with comments to help you understand it:
// Create array with the numbers that we have randomly generated
NSArray *randomNumbers = [[NSArray alloc] initWithObjects:#"0",#"1",#"1",#"2",nil];
NSMutableDictionary *occurenceDict = [[NSMutableDictionary alloc] init];
for (NSString *number in randomNumbers)
{
// If this number has not been added to the dictionary
if ([occurenceDict objectForKey:number] == nil) {
// Add it
[occurenceDict setValue:[NSNumber numberWithInt:[number intValue]] forKey:number];
// Find how many times the number occurs with the "randomNumbers" array
int occOfNum = 0;
for (int i = 0; i < [randomNumbers count]; i++) {
NSString *currentNumber = [randomNumbers objectAtIndex:i];
if ([currentNumber compare:number] == NSOrderedSame) {
// We found this number at this index, so increment the found count
occOfNum++;
}
}
// Save the number of times which "number" occurs in the dictionary for later
[occurenceDict setValue:[NSNumber numberWithInt:occOfNum] forKey:number];
}
}
// Iterate through all items in the dictionary and print out the result
for (NSString *key in occurenceDict) {
NSString *occurrences = [occurenceDict objectForKey:key];
NSLog(#"Number %d is contained %d", [key intValue], [occurrences intValue]);
}
// Release alloc'ed memory
[randomNumbers release];
[occurenceDict release];

Answer 3

Crikey, these answers are long-winded! Put your random generated numbers into an NSIndexSet. Test the set before inserting a number and you'll know that the number is already present, and so is a dupe.