Question

Here is a program

#include <stdio.h>
main()
{ unsigned char i=0x80;
printf("i=%d",i<<1);
}

The output it is giving is 256.
I am not clear with what does

unsigned char i=0x80; <-- i is not int it is char so what will it store?

I know bitshift and hexadecimal things.
How is the value of i being stored and how does it gets changed to 256?

UPDATE

Why did overflow not occurred when the bit shift operation happened?

Answer 1

In C, a char is an integer type used to store character data, typically 1 byte.

The value stored in i is 0x80 a hexidecimal constant that is equal to 128.

An arithmetic operation on two integer types (such as i << 1) will promote to the wider type, in this case to int, since 1 is an int constant. In any case, integer function arguments are promoted to int.

Then you send the result to printf, with a %d format specifier, which mean “print an integer”.