c - When displaying the value of variable "int a = 011", I get 9. Why? -

this question has answer here:

• what mean when numeric constant in c/c++ prefixed 0? 7 answers
• printf “%d” of numbers starting 0 (ex “0102”) giving unexpected answer (ex '“66”) 3 answers

with code snippet:

int = 011; printf("a = %d", a); 

why result

a = 9

011 octal value , decimal equivalent 9. preceding integer literal 0 indicates octal value.
use %o specifier in printf print value in octal.