C Programming - Declarations and Initializations - Discussion

Can anyone explain the answer of this: z = (x++ + ++x)x = 2. And z = (++x + x++)x = 2.

Its too late and ignore if not but it shouldn't be like this:

If x = 2.

z = x++ + ++x // here because x = 2, value 2 is assign to x (value 2 stored to perform overall function) n stored after that it'll increment by 1.

=> z = (2) ++.

That will 3. Till z = x++ value of x is 3.
After that z = 3 + ++x //till here x = 3.

So further by pre-increment 3 will incremented by 1 value will be 4. So z = 2 + 4 = 6.

Static variable are the variable which allocate the memory as well as program start and they create only one copy for more then object.

Why external linkage means global, non static, functions?
Why internal linkage means static variables, functions with filescope?
Why none linkage means local variables?

Please give clear information about those three.

What is the difference between non static variable and local variable?

What is difference between all three ?

In one interview TR asked me to write a program that prints its source code, after that I got that program in c programing app in play store but i can't understand the program.

Print Source Code - /* Write a program that prints its own code as the output */

#include<stdio.h>

int main() {
FILE *fp;
char c;

fp = fopen(__FILE__,"r");

do{
c= getc(fp);
putchar(c);
}
while(c != EOF);

fclose(fp);

getch();
return 0;
}

And in the app he showed same program as output including the #include everything how is it possible anyone please explain?

What are linkages?

what about the following:

int i=5;
printf("%d",(++i + ++i);
it is printing 13.

While as:

int i=5,z;
z=(++i + ++i);
printf("%d",z);
prints 14.

Can anyone explain why?

Hey guys x++ + ++x though we are making changes to x that will be updated in register because of optimization it treats both x as same value and makes z=x+x;

x++=value is incremented after the statement completes and x=2.
After ++x= pre inc so x in inc and x value is 3 and is stored in only one place now addition happens z=x+x,z=3+3=6;

But if you use volatile in front of int x; then it will give z=5;