C Assignment operator puzzle

Hello…been a long time since i posted anything. Excuses apart, (most bloggers have interesting excuses..but yes it is always about – getting busy living not getting busy blogging!) here is a nice puzzle to ponder about.

The code below shows a common mistake by most beginners. For eg in this snippet:



int rateofinterest, years, amt;/*some code here*/
…

if(years=6) printf(“rate of interest =5%”);

else if (years=5) printf(“rate of interest=7%”);

else printf(“invalid”);

you all know the output: it would always be rate of interest=5%. The compiler has no problem with this because a comparison operator has simply been replaced by an assignment operator. No harm done..however a similar mistake like the code below results in something weird.



int iresult, inum;scanf(“%d”,&inum);

iresult=inum%2;

if(iresult=0) printf (“even”);

else printf(“odd”);

Here, strangely the output is always “odd”. Why?