Strange behavior of increment operator in c language

Question

Look at this code the code below it has a strange behavior the output should be 18 but when i try to compile and run it in Turbo C or in Code::Block the output is 19 instead of 18.

int main() {
    int n=4, x;
    x = ++n + ++n + ++n;
    printf("%d", x);
    return 0;
 }

Can some explain it to me How the output is 19 instead of 18.

Note: when i try to run same code in java the output is 18 as expected.

But in c/c++ the output is 19 please explain

Thanks in Advance.