programming tips #1 : conditional expression (for c & c++)

ASSALAMMUALAIKUM W.B.T. peeps !

frankly, i'm inspired to share this on my blog bcoz on this evening, i got programming test and.... i'm stucked at this question. lol! never expect this one to be questioned on test... T.T k, my bad..


after finishing the test & went back to my room, i started to do some coding bout it to understand more. and now here i am, wanting to share to you all what i got.

so, first of all. what is conditional expression?  well, it is an expression that use conditional operators.

conditional operators are basically  ? and : symbols.

what are they used for? 
they are used to simplify or shorten if...else statement.

how?
here's the syntax >>

condition ? true case : false case

comparing it with an if..else statement;

if(condition)

   true case;

else

   false case;

got it? yes? congrats, fast-learner!

no? it's ok, let's move on with a simple example..

suppose there's a if...else statement;

if(marks>50)
   pass++; //increase number of student passed by 1
else
   fail++; //increase number of student failed by 1

converting this using conditional expression;
marks>50 ? pass++ : fail++ ;

condition before the ? will be tested. if true, execute pass++ (statement between ? and :). else, execute fail++ (statement after :) .


next example.. printing output.
from;

if(weight>65)
   cout<<"Fat!!"; 
else
   cout<<"Gorgeous!"; 

from what we had learnt before, converting this using conditional expression;
weight>65 ? cout<<"Fat!!" : cout<<"Gorgeous!" ;

but! there's a simpler way of doing this;
cout<<(weight>65 ? "Fat!!" : "Gorgeous!") ;

note that the second way we need to put brackets so the compiler will give priority to the conditional expression first.

same goes in c language;

from;

if(weight>65)
   printf("Fat!!"); 
else
   printf("Gorgeous!");

converting to conditional expression;
mark>50 ? printf("PASS") : printf("FAIL"); 

or putting the conditional expression inside printf;
printf(mark>50 ? "PASS" : "FAIL");

note that for the second way we did not need to put extra bracket (comparing to c++). bracket from the printf is enough.


all of examples above are the simple ones. of course, those that went out in my exam earlier is much more complicated. ~.~

such as (using c++):

if(cpa>3.0)
{
   if (cpa>3.5)
      cout<<"Dean's List";
   else
      cout<<"Second Class";
}
else
{
    if(cpa>2.0)
       cout<<"Passed";
    else
       cout<<"Failed!"; 
}

converting to conditional expression;
cout<<(cpa>3.0?cpa>3.5?"Dean's List":"Second Class":cpa>2.0?"Passed":"Failed");

if you compare both thoroughly, you can see that is just follow the flow as the if....else statement. line by line. and this is the example for nested if...else.


last example,
(using c language);

if(height>170)
{
   printf("So tall!") ; 
   tallpeople++ ; //increase number of tall people by 1
}
else
{
   printf("Hi shorty.") ;
   shortpeople++ ; //increase number of short people by 1
}

converting to conditional expression;
height>170 ? printf("So tall!") , tallpeople++ : printf("Hi shorty.") , shortpeople++ ;

or

printf(mark>50 ? "So tall!",tallpeople++ : "Hi shorty.",shortpeople++);

this example is actually for if...else with compound statements. we just need to put comma ',' between these statements.

final note, spaces between conditional operators are not necessary, but it'll make your coding easier to read.. as malay words, "sedap mata memandang" :3


that's all for tonight. hope this helps to enhance your knowledge. ^^


till we meet again!

regards,