order-of-evaluation

Could anyone explain these undefined behaviors (i = i++ + ++i , i = i++, etc...)

int main(int argc, char ** argv) { int i = 0; i = i++ + ++i; printf("%d\n", i); // 3 i = 1; i = (i++); printf("%d\n", i); // 2 Should be 1, no ? volatile int u = 0; u = u++ + ++u; printf("%d\n", u); // 1 u = 1; u = (u++); printf("%d\n", u); // 2 Should also be one, no ? register int v = 0; v...

How do we explain the result of the expression (++x)+(++x)+(++x)?

x = 1 i expect the answer to be 11, but it comes out to be 12. ...

C programming: is this undefined behavior?

Our class was asked this question by the C programming prof: You are given the code: int x=1; printf("%d",++x,x+1); What output will it always produce ? Most students said undefined behavior. Can anyone help me understand why it is so? Thanks for the edit and the answers but I'm still confused. ...

Input Puzzler in C

Possible Duplicate: Could anyone explain these undefined behaviors (i = i++ + ++i , i = i++, etc) int main() { int a=5,s; s=++a + ++a; printf("%d",a); printf("%d",s); } output is 7 and 14 BUT int main() { int a, s; printf("Enter value of a"); scanf ("%d",&a); s=++a + ++a; printf("%d",a); printf("%d",s); } input user give...

i=i-- -- does gcc document, which will be done

Hello Once again, our best loved "i=i--" -like issues. In C99 we have: 6.5 Expressions #2: Between the previous and next sequence point an object shall have its stored value modified at most once 70) This paragraph renders !!undefined!! statement expressions such as i = ++i + 1; But for undefinded behavior there ca...

Is this code undefined behavior?

Hi, after reading about sequence points, I learned that i = ++i is undefined. So how about this code: int i; int *p = &i; int *q = &i; *p = ++(*q); // that should also be undefined right? Let's say if initialization of p and q depends on some (complicated) condition. And they may be pointing to same object like in above ca...

difference between c's expression and c++'s expression

int main() { int i=3; (++i)++; printf("%d",i); } This programs works with g++ compiler but not gcc. If i write i++++ or ++i++ it doesn't work in cpp also. I think there is difference between c-expression and c++-expression. Can somebody explain about L-value and R-value ? ...

Is this program having any sequence point issues ?

#include<stdio.h> int main() { int i=7,j; j=(i++,++i,j*i); return 0; } j=(i++,++i,j*i);Is this well defined ? Let me clear my doubt. ...

Why does this C program give unexpected output?

Possible Duplicate: C programming: is this undefined behavior? #include<stdio.h> main() { int i=5; printf("%d%d%d",i,i++,++i); } my expected output is 556. But when i executed it the result is 767. how? ...

Explanation of ++val++ and ++*p++ in C

int val = 5; printf("%d",++val++); //gives compilation error : '++' needs l-value int *p = &val; printf("%d",++*p++); //no error Could someone explain these 2 cases? Thanks. ...

Multiple preincrement operations on a variable in C++(C ?)

Why does the following compile in C++? int phew = 53; ++++++++++phew ; The same code fails in C, why? ...

why "++x || ++y && ++z" calculate "++x" firstly ? however,Operator "&&" is higher than "||"

Why ++x || ++y && ++z calculate ++x firstly? However,Operator && is higher than ||? ...

Potential Problem in "Swapping values of two variables without using a third variable"

I recently came along this method for swapping the values of two variables without using a third variable. a^=b^=a^=b But when I tried the above code on different compilers, I got different results, some gave correct results, some didn't. Is anything terribly wrong with the code? ...

which side of the expression gets evaluated first?

Will the right side of the expression get evaluated first or the left ? void main () { int i = 0 , a[3] ; a[i] = i++; printf ("%d",a[i]) ; } ...

contradiction between c-faq and my compiler

The C-faq says that the code: int i = 7; printf("%d\n", i++ * i++); prints 49. Regardless of the order of evaluation, shouldn't it print 56? When I ran this code on my Turbo C 3.0 compiler it gave me the output of 56. Why is there a contradiction? ...

Function passing arguments in reverse

Here is my function: void abc(char *def, unsigned int w, unsigned int x, unsigned int y, unsigned int z) { printf("val 1 : %d\n", w); printf("val 2 : %d\n", x); printf("val 3 : %d\n", y); printf("val 4 : %d\n", z); } and here is where I call this function: unsigned int exp[4] = { 1, 2, 3, 4 }; unsigned short count = 0; a...

++i + ++i + ++i in Java vs C

Possible Duplicate: How do we explain the result of the expression (++x)+(++x)+(++x)? int i=2; i = ++i + ++i + ++i; Which is more correct? Java's result of 12 or C = 13. Or if not a matter of correctness, please elaborate. Thank you. ...

Difference between i = ++i and ++i

Possible Duplicate: Could anyone explain these undefined behaviors (i = i++ + ++i , i = i++, etc) What is the difference between i = ++i; and ++i; where i is an integer with value 10? According to me both do the same job of incrementing i i.e after completion of both the expressions i =11. ...

Please explain the output of this program

Possible Duplicate: Could anyone explain these undefined behaviors (i = i++ + ++i , i = i++, etc) I am using Visual C++ 6.0 and facing trouble predicting the output of the following program: int main(int argc,char **argv) { int a; int b; a=1; b = (++a) + (a++) + (a++); printf("%d",b); return 0; } ...

In what order does Scheme code run?

We've been taught various syntax and told how to write definitions, but we've never written any code an ran it. What is the order that Scheme code runs in? Thanks! ...