Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
474 views
in Technique[技术] by (71.8m points)

c - Are all char arrays automatically null-terminated?

Probably I'm just too dump for googling, but I always thought char arrays get only null terminated by an literal initialization (char x[]="asdf";) and got a bit surprised when I saw that this seems not to be the case.

int main()
{
    char x[2];
    printf("%d", x[2]);
    return 0;
}

Output: 0

Shouldn't an array declared as size=2*char actually get the size of 2 chars? Or am I doing something wrong here? I mean it isn't uncommon to use a char array as a simple char array and not as a string, or is it?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

You are accessing an uninitialized array outside its bounds. That's double undefined behavior, anything could happen, even getting 0 as output.

In answer to your real question: Only string literals get null-terminated, and that means that char x[]="asdf" is an array of 5 elements.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

2.1m questions

2.1m answers

60 comments

57.0k users

...