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why is sizeof() an operator and not a function ?

+2 votes
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why is sizeof() an operator and not a function ?
posted Sep 6, 2013 by Ganesh Kumar

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It's not possible to write a function that can take a type as an argument a function can take only variable as output.
commented Sep 6, 2013 by Salil Agrawal

1 Answer

+1 vote
 
Best answer

Sizeof() is a compile time operator. To calculated size of an element (either for inbuilt data type or user defined data type) type information is necessary at the compile time along with operating system information(32 bit or 64 bit). After compilation phase, compiler generates object code. object code doesn't has type information. while executing sizeof() just return calculated size of object then we use malloc, calloc etc function to allocate memory dynamically.

answer Sep 6, 2013 by Vimal Kumar Mishra
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