What is the output of the following C code?

Question

  int main (){      int a=5,b=3;      printf("%d", a+++++b); // 5 +'s  }

Please Explain.

Answer 1

 https://stackoverflow.com/questions/5341202/why-doesnt-ab-work-in-c 

printf("%d",a+++++b); is interpreted as (a++)++ + b according to the Maximal Munch Rule^!.

++ (postfix) doesn't evaluate to an lvalue but it requires its operand to be an lvalue.

_{! 6.4/4 says the next preprocessing token is the longest sequence of characters that could constitute a preprocessing token"}

- Prasoon Saurav

Comments

That i also know even a+++ ++b will give same result but a+++++b not

the reason i want to know!

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simply to say its not a valid lexical unit. note: lexical unit always tries to find longest valid lexical unit. after lexical analyzer sees + after a , it identifies a as identifier (variable) , and try to identify next token ++++++b it is not valid token. as space is separator , if you give space a++ + ++b , it identifies a as variable and ++ as operator and + as operator and b as identifier.

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ok!! http://stackoverflow.com/questions/5341202/why-doesnt-ab-work-in-c for more i found this!!

Answer 2

see this code :

  #include<stdio.h>  int main (){      int a=5,b=3;      printf("%d", a++++); // 5 +'s  }

Now here see the analysis first we have a++ ,no issue we got a=5 ,now what I did is 5++ which is blunder since post-increment returns rvalue and for any further operation I need lvalue for it ,therefore it is an error  post-increment .

Also you can see that when we write a++ it is evaluated as a=a+1 ,but when we write 5++ it makes no sense since it would be 5=5+1 ,which is invalid ,hence lvalue required

please refer to this link once .

http://stackoverflow.com/questions/17440117/confused-with-pre-and-post-increment-operator