c - Why is it printing semi colon(;)? -

the below program when executed printing ';' output. not understanding why. when changing value of 'c' , 'i', adding 2 , printing symbols '=' , ';'

#include<stdio.h>  int main() {     char c='1';     int i=10;     printf("%c", c|i); } 

because 49 | 10 = 59 , 59 ascii code of ';'.