: symbol in c structure and it uses

Asked May 09 '20 at 17:22

Active May 09 '20 at 17:25

Viewed 493 times

Whats does the : symbol means in c structure. The code below supposed to show output 12 (size of int=4,size of structure=sum of each structure member)

But it is showing 8 as output.

#include<stdio.h>

typedef struct
{
int bit1:20;
int bit2:1;
int bit30:30;
} bits;

int main()
{
printf("%d",sizeof(bits));
}

But when i change the value

int bits30:30;

Into

int bits30:40;

It is showing an error,what is the use of : in c structure.

asked May 09 '20 at 17:22

Dora

https://stackoverflow.com/questions/24933242/when-to-use-bit-fields-in-c – s4eed May 09 '20 at 17:24
I found the linked questions by googling for "stackoverflow c struct colon". – John Kugelman May 09 '20 at 17:26
BTW, since you tagged as C++, you don't need `typedef struct` in C++. – Thomas Matthews May 09 '20 at 18:46
When dealing with bits, you should prefer `unsigned int` to `int`. You don't want to mess with the interpretations of the sign bit. – Thomas Matthews May 09 '20 at 18:47

: symbol in c structure and it uses

0 Answers0