[Interview Summary] The magical strlen() function

The problem is this:

char s[] = "\\123456\123456\t";
printf("%d\n",strlen(s));
A 12 B 13 C 16 D None of the above

correct answer:B
Investigate the knowledge points: the role of the escape character, first is an escape character \, plus 123456 at this time the length is 7, and then another escape character \123means that the {length is 8, plus 456, the length is 11. Plus the \tlength is 12, and the ending symbol \0is just 13 at the end.