programing

Question

 

int main(){
    int a;
    a = 1;
    while(a-- >= 1)
    while(a-- >= 0);
    printf("%d", a);
}    

Answer 1

intially a=1 then due to inside while loop use post decrement operator which means firstly assign the value then decrement so firstly

while(1==1)true the decrement 'a' by 1 then a become 0 then while(0=0) true then  'a' decrement by 1 by which  a=-1 then go inner while loop  while(-1=0) false then decrement then  a=-2 then go outer while loop again condition false and finally  'a' become -3

so answer is  a=-3

Answer 2

a=-3

a-- first use then change the value of a 

Answer 3

Here -- is a post decrement operator

So, in while loop (a>=1) which is true , then a-- gives 0

go to second while loop until get a semicolon

second while loop gets a value as 0

then (a>=0) which is true

then a--

So, after second while loop value of a becomes -1

But for semicolon it cannot go outside of second while loop.

Go to first while loop again (a>=1)  condition false and a becomes -2

Go to second while loop ,again condition false and a becomes -3

Now go outside of while loop and print -3

Comments

So, after second while loop value of a becomes -1

But for semicolon it cannot go outside of second while loop.

Go to first while loop again (a>=1)  condition false and a becomes -2

Go to second while loop ,again condition false and a becomes -3

Now go outside of while loop and print -3

Inner while loop does 2 iterations - a changes to -1 and to -2 here. Now the outer while loop makes a = -3 and the loop exits.