how to check the greater value in iphone application

Question

I am creating graph i get 5 values at run time so how should i know which is greater so that i may set max limit I have following 5 varibale of values;

    int value3=(int)roundf(appDelegate.itemOneValue);
    int value4=(int)roundf(appDelegate.itemTwoValue);

    int value5=(int)roundf(appDelegate.itemThreeValue);

    int value6=(int)roundf(appDelegate.itemFourValue);

    int value7=(int)roundf(appDelegate.itemFiveValue);

how to check of the above varible which has larger value.

Hermann Klecker · Accepted Answer · 2012-12-18T10:41:37.600

2

NSArray *allValues = @[[NSNumber numberWithInt:(int)roundf(appDelegate.itemOneValue)], 
    [NSNumber numberWithInt:(int)roundf(appDelegate.itemTwoValue)], 
    [NSNumber numberWithInt:(int)roundf(appDelegate.itemThreeValue)], 
    [NSNumber numberWithInt:(int)roundf(appDelegate.itemFourValue)],
    [NSNumber numberWithInt:(int)roundf(appDelegate.itemFiveValue)]];

int max = [[allValues valueForKeyPath:@"@max.intValue"] intValue];

or

NSNumber * max = [allValues valueForKeyPath:@"@max.intValue"];

An alternative that is less flexible but may be easier to understand:

int max = (value2 < value1) value2 : value1;
max = (value3 < max) value3 : max;
max = (value4 < max) value4 : max;
max = (value5 < max) value5 : max;
max = (value6 < max) value6 : max;
max = (value7 < max) value7 : max; 
// now max contains the highest of all values.

edited Dec 18 '12 at 10:41

answered Dec 18 '12 at 09:26

Hermann Klecker

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+1. very good, but IMHO it's too advanced for the question! :) – elp Dec 18 '12 at 09:29
// max = (value3 > value4) ? value3: value4; // max = (value5 > value6) ? value5: value6; //max = (max > value7) ? max: value7; – user1808433 Dec 18 '12 at 09:49
i am using like this is it ok or not – user1808433 Dec 18 '12 at 10:05
but it is showing wrong answer i am posting code you can see – user1808433 Dec 18 '12 at 10:22
@HermannKlecker i have posted code in your answer please look at that – user1808433 Dec 18 '12 at 10:23
Please do not update my answer. You may update your question. And no, your code example does not work. If either value3 or value4 is the maximum then this information would get lost in the very next line of your code. Why don't you go with my second alternative? – Hermann Klecker Dec 18 '12 at 10:40

score 0 · Answer 2 · edited May 23 '17 at 12:04

You can read a great article on wikipedia: http://en.wikipedia.org/wiki/Selection_algorithm

Here the pseudo-code to get min/max from an array:

 function select(list[1..n], k)
     for i from 1 to k
         minIndex = i
         minValue = list[i]
         for j from i+1 to n
             if list[j] < minValue
                 minIndex = j
                 minValue = list[j]
         swap list[i] and list[minIndex]
     return list[k]

In objc, the pseudo code became something like this:

  int value3=(int)roundf(appDelegate.itemOneValue);
  int value4=(int)roundf(appDelegate.itemTwoValue);
  int value5=(int)roundf(appDelegate.itemThreeValue);
  int value6=(int)roundf(appDelegate.itemFourValue);
  int value7=(int)roundf(appDelegate.itemFiveValue);

  NSArray *values = @[[NSNumber numberWithInt:value3],
                      [NSNumber numberWithInt:value4],
                      [NSNumber numberWithInt:value5],
                      [NSNumber numberWithInt:value6],
                      [NSNumber numberWithInt:value7]];
  NSNumber min=0;
  NSNumber max=0;
  for ( int i=0; i<[values count]; i++ ) {
    min = [values objectAtIndex:i];
    //etc...
    for (int j=0; j<i+1; j++ ) {
      if ( [values[j] > min] ) {
        // etc..
      }
    }
  }

hope this helps.

can you explain this algorithm in simple logic using objective c — user1808433, Dec 18 '12 at 09:17

how to check the greater value in iphone application

2 Answers2