Why are two strings evaluated as one concetinated string

Asked Feb 19 '18 at 12:33

Active Feb 19 '18 at 12:33

Viewed 68 times

Is is "Hallo" " Welt" equivalent to "Hallo Welt"?

Should is the following code throw any error or warning at compile time?

#include <iostream>

void print(std::string s) { 
    std::cout << s; 
}

int main() {
    print("Hallo" " Welt");
}

Using icc 15.0.3 and -Wall no error or warning is thrown and it prints out Hallo Welt.

The background of my question is that clang-format has broken a long string into two, like in the example above.

What happens in C using char*?

asked Feb 19 '18 at 12:33

schorsch312

3

If you want a formal answer you need to pick *one* language. – Some programmer dude Feb 19 '18 at 12:35
1

Perfectly legal. A C99 extension, if I recall. The compiler concatenates adjacent strings at compile time. – Steve Summit Feb 19 '18 at 12:35
2

@SteveSummit It's been the same at least since C89. – P.P Feb 19 '18 at 12:36
"*What happens in `C` using `char*`?*" why not just try it? – alk Feb 19 '18 at 13:10
2

@alk Please remember that "just try it" is dubious advice -- for example, it's the last thing you want someone do do when they're wondering what the "correct" behavior of `i++ + i++` is. – Steve Summit Feb 19 '18 at 13:13
@SteveSummit: agreed. But here the context obviously is different.And even more would lead to defined bahaviour. – alk Feb 19 '18 at 13:18

0 Answers0