Re: "undefined behavior"?

Janis Papanagnou <janis_papanagnou+ng@hotmail.com> writes:

On 12.06.2024 22:47, DFS wrote:

[...]

before: char outliers[100];
after : char outliers[100] = "";

[...]

Seriously; why do you expect [in C] a declaration to initialize that
stack object? (There are other languages that do initializations as
the language defines it, but C doesn't; it may help to learn before
programming in any language?) And why do you think that "" would be
an appropriate initialization (i.e. a single '\0' character) and not
all 100 elements set to '\0'? (Someone else might want to access the
element 'answer[99]'.) And should we pay for initializing 1000000000
characters in case one declares an appropriate huge array?

This:
    char outliers[100] = "";
initializes all 100 elements to zero.  So does this:
    char outliers[100] = { '\0' };
Any elements or members not specified in an initializer are set to zero.

If you want to set an array's 0th element to 0 and not waste time
initializing the rest, you can assign it separately:
    char outliers[100];
    outliers[0] = '\0';
or
    char outliers[100];
    strcpy(outliers, "");
though the overhead of the function call is likely to outweigh the
cost of initializing the array.

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */