C Programming - Expressions - Discussion

Discussion Forum : Expressions - General Questions (Q.No. 3)
3.
Which of the following is the correct usage of conditional operators used in C?
a>b ? c=30 : c=40;
a>b ? c=30;
max = a>b ? a>c?a:c:b>c?b:c
return (a>b)?(a:b)
Answer: Option
Explanation:

Option A: assignment statements are always return in paranthesis in the case of conditional operator. It should be a>b? (c=30):(c=40);

Option B: it is syntatically wrong.

Option D: syntatically wrong, it should be return(a>b ? a:b);

Option C: it uses nested conditional operator, this is logic for finding greatest number out of three numbers.

Discussion:
30 comments Page 1 of 3.

Afsheen said:   2 decades ago
If b>c then b is true else c is true, so 1st b>c is evaluated and stored then a>c is evaluated and stored. now the whole expression is considered.

Let us assume

(i) in b>c case this stmnt is true so b is saved.
(ii)in a>c case this stmnt is false so c is saved.
now the expression is in the form
max=a>b?c:b

Now finally this is evaluated.
you just assume the given stmnt as a>b?(a>c?a:c):(b>c?b:c).

I hope you understood.

Ramu said:   1 decade ago
Simply we have to think in general if..else format

like if(a>b)
{
if(a>c)
max is a
else
max is c
}
else if(b>c)
max is b
else
max is c

This is implemented , thinking in this we could easily analyse for greatest of 3 or 4 or 5 and so on easily I think so.

Guddu said:   9 years ago
I think option C is completely right.
Whereas option A having problem.

main.c:6:18: error: lvalue required as left operand of assignment
a>b ? c=30 : c=40; here "c=40" having problem.

Shashank said:   1 decade ago
What if in 'max = a>b ? (a>C ? a : c) : (b>c ? b :c)'

c is greater than both a and b, then the equation will be

max = a>b?c:c

Then how would the statement be evaluated? though the answer is C, I want the steps compiler takes to evaluate it.

Husain said:   5 years ago
A is not the correct answer. It will always generate the error of lvalue required
instead righteous way to write statement A is;
c=a>b?30:40;

Of course, C, the option can also be termed wrong in syntax for not terminating it with a semicolon.
(2)

DEVIPRIYA said:   1 decade ago
Max = a>b?(a>c?a:c):(b<c?b:c).

First it checks a>b if condition is true then Max = (a>c?a:c).

Else Max = (b<c?b:c).

Again it checks the condition like this.

Hemant said:   8 years ago
If they are being so specific about parenthesis. They should also include a semicolon in the end of their result mentioned. Because I believe the first option will also work.

AdamK said:   10 years ago
Condition operators does not require strictly the "()"s. And there is a syntax error in option C, just like @Azhar mentioned. Between A and C, personally I tend to choose A.

Durga said:   1 decade ago
I am not under stand please clear about it. In detailed because I don't know how to use ? opearator. So plese clear with a example how to use this operator.

Sivarenjini said:   7 years ago
C option is also wrong.

There must be semicolon at the end. Then only it can be considered as valid.
(3)


Post your comments here:

Your comments will be displayed after verification.