Why is it displaying extra characters?

Question

C++ / C#

If I set an array 'butt' , then when displaying its contents, it displays extra characters on the screen

char L[4] = {'a','b','c','d'};
printf("%s\n", L);

conclusion:
Why does he actually display them?
And is there any way to fix this without increasing the size of the array?

Answer 1

It should be 0 at the end. Like this: Or like this:
char L[] = {'a','b','c','d', '\0'};