can you give another logic?

[crocker]

Hi friends,

i tried to solve the logics for the question " write a c program to find max of 3 numbers with out using ">" and "ternary operators" " . For this i got one logic as

1. first i converted given numbers to strings.

2. i find the max of two numbers by compaing the strcmp() function library.( strcmp(s1,s2) returns 0 if s1 equal to s1, -1 s2 greater than s1 , 1 s1 is greater than s2)

3. i used switch case after strcm() library

from above steps i can find max of 3 numbers


can any one suggest me another logics .


i look for your further replys

[MK27]

strcmp(s1,s2) returns 0 if s1 equal to s1, -1 s2 greater than s1 , 1 s1 is greater than s2)
can any one suggest me another logics .

strcmp() DOES NOT work that way.

You say you can't use > greater than. Can you use < less than?

[Adak]

He has a typo, but yes, strcmp() does *sometimes* work that way. The 1 and -1 is not defined by the standards of C, but are sometimes used by compilers as the returned values. (turbo C does, for instance).

if your teacher's compiler does NOT use 1 and -1 for these strcmp() returned values, then you're sunk, of course.

Are you sure that your teacher's compiler's strcmp() will return 1 and -1?

[crocker]

hi i think,

incase of -1 its return any negative value and incase of 1 it return any positive value may correct ?


i want ur suggestions

[jeffcobb]

max(a,b)?

[MK27]

He has a typo, but yes, strcmp() does *sometimes* work that way.

Okay, my mistake. In fact it is part of the standard:

7.21.4
The sign of a nonzero value returned by the comparison functions memcmp, strcmp,
and strncmp is determined by the sign of the difference between the values of the first
pair of characters (both interpreted as unsigned char) that differ in the objects being
compared.

So that's all good.

[Adak]

hi i think,

incase of -1 its return any negative value and incase of 1 it return any positive value may correct ?


i want ur suggestions

Yes, it's not always just a 1 or a -1.

So, moving along, I haven't looked into it, but Jeff's idea of using max(), sounded MUCH better, still.

Let's go with that puppy.

[Salem]

But max() or strcmp() will both involve < > or ?:

So are you really meeting the objective, by hiding your implied use of these operators?

[jeffcobb]

But max() or strcmp() will both involve < > or ?:

So are you really meeting the objective, by hiding your implied use of these operators?

Its hard to say; sometimes an instructor will try to get a student to think outside the box and sometimes they are trying to lead them to the obvious answer....only the OP knows for sure...

[Adak]

Whatever you use to sort values, it will imply at some level, a > or <, imo.

So of course, we're hiding it. I thought that was the name of this game, no?

[MK27]

How about this:

Use an infinite loop. Add one to each number until one or more of them == INT_MAX. That number is the highest. If two+ numbers equal zero in the same iteration, they are the same number.

Real inefficient, but there's no < or >.

[C_ntua]

How about this:

Use an infinite loop. Add one to each number until one or more of them == INT_MAX. That number is the highest. If two+ numbers equal zero in the same iteration, they are the same number.

Real inefficient, but there's no < or >.

This assumes they are integers, which might not be the case.

You can simply use bitwise operators for integers. Start searching who has "1" at the highest position.
You can do soething similar for floats.

You could also substract and check the one from another. Then do
result & 10000...
if the result is 1000.... it is negative, thus the second is bigger. Otherwise the first. You should check also the
result | 00000...
and/or
result | 10000...
to check for the result being zero. Thus both numbers are equal

Bitwise operators don't involve the < symbol at all. Neither the >

Of course, the simple answer to the OP, as already mentioned is to use < :P

[MK27]

You can simply use bitwise operators for integers. Start searching who has "1" at the highest position.

I thought about that, but won't work very well because it will be too easy for two numbers to tie.

However, I guess you could keep iterating and the first positive XOR indicates a tie breaker. Maybe that was really the point of the assignment.

[C_ntua]

I thought about that, but won't work very well because it will be too easy for two numbers to tie.

However, I guess you could keep iterating and the first positive XOR indicates a tie breaker. Maybe that was really the point of the assignment.

True. And you will have to take under consideration how negatives are represented. Usually the first digit shows signs (1 for negative).

[Adak]

That caffeine must be working on ya'll. Very creative!