Why the output contains inrrelevent characters ?

Question

The output contains irrelevent characters if only 0 index of array is initialised ..
If index from 0-3 is initialised here then there is no abitrary characters !
https://code.sololearn.com/cRMR2D3x9GkS/?ref=app

Answer 1

An array is allocated memory.
C does not initialise its memory automatically.

So what you see is left over data from the previous owner of that memory. Which is rubbish and a potential threat of bugs.

Especially in C always initialse the variable's you are going to use,

Answer 2

Martin Taylor
Since my char array has 6 characters and I've initialised only first character then why only 2 or 3 random characters are printed instead of all the remaining 5 ?
And since I've not mentioned a null character in my char array why the printf() has stopped printing characters after those 2 or 3 garbage characters. ?