C quiz questions

[ayanbizz]

I need help with the following questions
1)

int z,x=5,y=-10,a=4,b=2; z = x++ - --y * b / a;

output?
2)

int a=10,b;b=a++ + ++a;printf("%d,%d,%d,%d",b,a++,a,++a);

I felt the answer would be 21,13,13,13 but the answer is 22,13,13,13.How b is coming as 22?
3)

void myFunc (int x) {    if (x > 0)   myFunc(--x); 
   printf("%d, ", x); } 
int main() 
{    myFunc(5);    return 0; }

I felt the answer should be 0, 1, 2, 3, 4, but is 0,0,1,2,3,4.How is the extra 0 coming?
4) why does 11 ^ 5 show 14
5)

int a=5;       a*=2+3

.here a should have been 13(5*2+3) but it is coming as 25.How?
6)

#include  int i;
 void increment( int i ) {    i++; } 
int main() { 
   for( i = 0; i < 10; increment( i ) )
    {    } 
   printf("i=%d\n", i);    return 0; 
}

Why is this creating an infinite loop?

[camel-man]

	
void myFunc (int x) {    if (x > 0)   myFunc(--x);
   printf("%d, ", x); }
int main()
{    myFunc(5);    return 0; }
I felt the answer should be 0, 1, 2, 3, 4, but is 0,0,1,2,3,4.How is the extra 0 coming?

it comes out 0,1,2,3,4 for me :/

[stahta01]

I suggest looking up operator precedent and pass by value.

C++ Operator Precedence - Cppreference

Tim S.

[jimblumberg]

I also suggest you read up on sequence points. At least one of your questions has undefined behavior.

Jim

[Salem]

> I felt the answer would be 21,13,13,13 but the answer is 22,13,13,13.How b is coming as 22?
Because the code is garbage, and has undefined behaviour.
Expressions

If your teacher "claims" to know an answer, find another teacher. You're not going to learn anything useful from them.

[anduril462]

1. Look up how pre/post increment and decrement work, and operator precedence. You can calculate this easily by hand. Give it a shot.
2. Read this link, particularly questions 3.2 and 3.3: Expressions.
3. Again, look up pre-decrement. Trace the code by hand, for each recursive call.
4. What does the ^ operator do? Look it up in your book.
5. Study operator precedence and order of operations.
6. Like Tim said, study pass by value and how it works.

@camel-man: Pay careful attention to where the recursive call happens in relation to the printf statement. Think of it like pre-order and post-order traversal in binary trees, if you're familiar with that.

[camel-man]

Yes I see that now thanks, Andruil462, how come when you change --x; to x-- it gives a seg fault?

[stahta01]

Yes I see that now thanks, Andruil462, how come when you change --x; to x-- it gives a seg fault?

Because it will then exhaust the stack space and crash the program.
Hint: No matter how many times the function is called with 5 it will always be greater than zero.

Tim S.

[KCfromNC]

I need help with the following questions
1)

int z,x=5,y=-10,a=4,b=2; z = x++ - --y * b / a;

output?

None, obviously.