CODEWITHSUNDEEP
cif-statement
vinay hunachyal
vinay hunachyal

Reputation: 3891

how the assignment is assigned for the if condition in below code

How this code works .Here i variable gets assignment of 55 value .But why the if statement fails since i gets 55 not 0, here else statement executed.How this interpretation happens . As i expected output is Test Skills 55but its not.

#include<stdio.h>
void main()
{
  int i;
  i=0;
  if(i=55,0,10,0)
  printf("Test Skills %d",i);
  else
  printf("C Programing %d",i);

 }

Can any one explain how it behaves in above code?

Upvotes: 1

Views: 590

Answers (3)

Arpit
Arpit

Reputation: 12797

, operator executes from left to right. So the last value is 0 that makes the if false.

if(i=55,0,10,0) => if(i,0,10,0) => if(55,0,10,0) => if(0) => which returns false
                                     ^^^^-> Value of i

i is still 55 because , has the lowest precedence .

, operator executes it's left expression and returns the result of right expression as a result of , operator.

Other thing to note here is assignment operator has higher precedence then ,. That's why i got the value 55.

Upvotes: 0

haccks
haccks

Reputation: 106042

The comma expression 

exp1, exp2

where exp1 and exp2 are any two expressions. This will evaluated in two steps:

  1. exp1 is evaluated and its value discarded.
  2. exp2 is evaluated and its value is the value of entire expression.

NOTE: Evaluating exp1 should always have a side effect; if it does not, then exp1 serves no purpose.

In your case 

if(i=55,0,10,0)

i=55 is evaluated first and its value discarded (but side effect to i has been done, i.e, 55 is assigned to i). 0 evaluated then and discarded. 10 evaluated then and discarded. After then right most 0 is evaluated and it will be the value of entire expression ((but not the value of sub-expressions)) in if condition and make the condition false.
But side effect to i has been done and that's why you are getting output as55.

Upvotes: 3

ST3
ST3

Reputation: 8946

The comma operator is left to right.

You have values: 55,0,10,0 and the right-most value is 0 that means false.

Also assignment operator has higher priority then comma, so i is set to 55.

Upvotes: 0

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