Question

Can someone please explain me why its not possible to put a '\0' character in the given array:

char a[]={'r','b'};

a[2]='\0';

Shouldn’t the above code put a null character at the third slot and hence convert the character array a to a character string.

Answer 1

You are writing past the array boundary: when you initialize an array with two characters, the last valid index is 1, not 2.

You should initialize your array with three items, as follows:

char a[] = {'r', 'b', '\0'};

You could as well use this version:

char a[] = "rb";

This will give you a writable array with a zero-terminated string inside.