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# what's the output of this? c*(b*(++a)--)

would be pleased if explain it step by step

11/28/2020 5:21:48 PM

athena

20 Answers

New Answer

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athena ++/-- are unary operators means those can be applied to single variable ++a or a-- But not applied to (b*(++a), this is compound statement, not a single variable. So there in (c*(b*(++a)--)) First in ++a is evaluated so a=a+1 so next a-- but this is post increment so value of a is used first in expression then after only a is decremented so value used in expression is a+1 but after expression a value is a = (a+1) - 1, (a+1) is result of ++a. So expression is evaluated as (c*(b*(++a)--)) =>(c*b*(a+1)--) =>(c*b*(a+1)), a =( a+1)-- =>c*b*(a+1) will give you result, and a = a+1 - 1= a; D_Stark Yes. (++a) -- => (a+1)-- => a+1-1=>a Preincrement value used in expression, post increment applied on pre incremented value because of braces.. It's invalid statement in java. And I think work only in c++. It's a unary operator works on single variable not on compound statement. Thank you..

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athena I posted an example code above step by step

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without checking I think it works like so... "a" is incemented by 1 value is used "b" is multiplied by "a" current value then "a" is decremented by 1 afterwards "c" is then multiplied by the the value of that was left from "b" and "a" including the decrement of "a" https://code.sololearn.com/c9WiZY0rGpUl/?ref=app

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Jayakrishna🇮🇳 hey, is the decrement taken from the variable "a" value or the value after the valuation im just curious as I cant use the decrement operator in this way in java as it looks for a variable but cant find one as it's been used. Thanks

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athena what I know is when the variables have been evaluated inside the parenthesis it becomes just a holding place for a number ie the result so.. a = 9 b = 5 c = 2 (a+(b+c)-1); the next step would look like so (a+7-1) and next step (15)

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Continuing.. athena In your code : int a=1; int b=3; int c=6; =>(c*(b*(a+1))) =>(6*(3*(1+1))) =>(6*(3*(2))) =>6*3*2 =>36 And c=6,b=3, a = (a+1)-1=a=1 again.. @athena hope it clears.. You're welcome...

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athena i just taken a sample values to show you how the expressions result.. There b, c values will not change but value of a change first by (++a) by one and after using the value a-- happens so a value comes to same of previous value.. You can take any values for a, b, c. ++/-- will applied to single operator. It is *unary operator. So affect only single operator, not applied to compound statements.. So b won't change.. Edit : that statement is valid in c++. But invalid in other languages mostly I think.....

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athena you'll have to show me your code

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》++a assigns the value of as a+1 and then proceeds. Therefore a becomes a+1 . 》(a+1)-- will reduce the value of a+1 after assihnment. So the value does not change the result will be c*b*a +c*b

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athena have a look at lvalue and rvalue this should sort your understanding why this statment executes as ++a is a lvalue so the refrenece to this object is still accessible.

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athena Have a look at this once for post/pre incrementation evaluation if you need to know.. Hope it helps.. https://www.sololearn.com/Discuss/1690694/?ref=app

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#include <iostream> using namespace std; int main() { int a = 2,b = 3,c= 4; cout<<(c*(b*(++a)--))<<endl; //this result to as : cout <<(4*3*3); //first it use ++a, then done a-- so (++a)-- => a=2, output=36 }

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D_Stark so after the increment which happens to a then we will have b=6 by multiplying then what will happen to the a? why the decrement will only effects on a? and not the b=6?

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Jayakrishna🇮🇳 why c is equal to 4?

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Jayakrishna🇮🇳 yeah I'm ok with that but i cant get how will -- affect on "a" and not "b*(++a)" and after multiplying b and a what will be the number that is gonna be multiplied by c

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D_Stark but i think the answer is 36 I am not sure at all

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https://code.sololearn.com/ciL0CP9K0PkW/?ref=app D_Stark

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Jayakrishna🇮🇳 thank you very much

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Jayakrishna🇮🇳 thank you very much ❤️

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You're welcome athena