Memory allocation im C

Question

I am interested im memory allocation in C language. I can't imagine how variable with allocated memory (malloc) behave when has bigger size than allocated bytes. Here is code:
int main() {
char* str = (char*) malloc(3);
strcpy(str, "Long sentence.");
printf("%s", str);
return 0;
}:

Answer 1

Always assume the worst: Your program will probably crash.

Answer 2

Now I understand, unpredictable results are unwanted forced changes in memory.

Answer 3

Sometimes I get Segmentation Fault but mostly program runs and able to corrupt other variable
If you are getting ERROR then try to re-run it
https://code.sololearn.com/cTiww2y4hfG9/?ref=app

Answer 4

Thanks for fast answer, so when allocated memory is too small for value like char array, it is re-allocated?