char charAt2(int index) {
writeFile(this, index);
return this.charAt(index);
}
method(s1.charAt2(x), s2.charAt2(y));
s1.charAt2(x) executes first, then s2.charAt2(y).
s2.charAt2(y) executes first, then s1.charAt2(x).
Dunno which executes first — better find out.
I might know which executes first but I don't care.