what is : operator ? what it does ? i know about scope resolution operator. it is written as :: but what is : operator ?
can anybody explain plz. i dont know the name of this operator.
if anybody give very simple example, will be glad.
probabily these are written inside a class.
thanks
blue_gene
There is no such thing as operator :
However, there is the ternary operator, which uses ? and :
If the expression evaluates to true, then the first value is returned, otherwise the second value is returned. I think you can overload the ternary operator for a class, but I think it is rarely a good idea.Code:#include <iostream> int main() { bool expression = true; char result = expression ? 't' : 'f'; std::cout << result << std::endl; expression = false; result = expression ? 't' : 'f'; std::cout << result << std::endl; int var = 10; result = var == 10 ? 't' : 'f'; std::cout << result << std::endl; var = 20; result = var == 10 ? 't' : 'f'; std::cout << result << std::endl; }
? : is the tertiary operator.
a < b ? a : b;
the above line is the equivalent of
if(a < b)
return a;
else
return b;
In more general terms it says if the conditional statement before the ? operator is true then return the variable before the : operator, else return the variable after the : operator.
: is also used as in initialization lists for classes, and maybe more. ? may be used for other purposes as well. But when used together, that's what it does.
>I think you can overload the ternary operator for a class
No, the ternary conditional operator is one of the operators that cannot be overloaded.
My best code is written with the delete key.
i am well aware of the ternary operator in C . i have seen these to use for the class constructor.i am sorry, i dont have the example right now . but is there any other way to use this operator in a class ? or any other application except this ?
blue_gene
>i have seen these to use for the class constructor.
You mean something like this?
The colon simply says that what follows will be an initialization list followed by the constructor body instead of just the constructor body. The ? operator is only used in conjunction with : as the conditional operator, but : is used elsewhere (bit fields, inheritance, labels).Code:myClass::myClass ( int a, int b, int c ) : mya ( a ) , myb ( b ) , myc ( c ) {}
My best code is written with the delete key.
exactly i was talking about that.
not clear.The colon simply says that what follows will be an initialization list followed by the constructor
what is the equivalent code of that ?
your brackets are not properly written probabily
blue_gene
>what is the equivalent code of that ?
In this case:
>your brackets are not properly written probabilyCode:myClass::myClass ( int a, int b, int c ) { mya = a; myb = b; myc = c; }
...
My best code is written with the delete key.
yes,latter one i know and that is very simple . i also read about initialization list from my book.
i wonder, how many ways a simple thing can be made complicated !! there are many syntaxes for the same thing!!
anyway, its fine....ok
thanks
blue_gene
>how many ways a simple thing can be made complicated !!
You really don't want to know.
>there are many syntaxes for the same thing!!
Well, when it comes to initialization lists, there is a purpose. Create a class with a const or reference member and see how far you get trying to initialize it in the constructor body.
My best code is written with the delete key.
You all forgot about when using switches
Code:switch(variable) { case something: statement; break; etc.
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>You all forgot about when using switches
>>but : is used elsewhere (bit fields, inheritance, labels)
My best code is written with the delete key.
You caught me prelude, I forgot about labels and bitfields, haven't done too much with inheritence yet, I still am learning c++. I guess the : operator is the misc. operator. Do all know all operator.
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