arrays - Why isn't the output right?

Question

This question already has answers here: question from:https://stackoverflow.com/questions/65871580/why-isnt-the-output-right

Answer 1

Assuming 4 byte ints here:

t.x = 0;

write four 0 bytes into the union. That overwrites all the elements in arr[].

t.arr[1] = 'G';

writes a 'G' into the second byte of the union. There are still 3 zero-bytes: one before the G and two after the G.

printf("%s", t.arr);

prints up to the first 0 byte in t.arr, which is the first byte in t.arr because you wrote 4 zeroes into the union. No output.