binary - How to look at a certain bit in C programming? -

i'm having trouble trying find function @ bit. if, example, had binary number of 1111 1111 1111 1011, , wanted @ significant bit ( bit way left, in case 1) function use @ bit?

the program test if binary number positive or negative. started off using hex number 0x0005, , using two's compliment function make negative. now, need way check if first bit 1 or 0 , return value out of that. integer n equal 1 or 0 depending on if negative or positive. code follows:

#include <msp430.h>  signed long x=0x0005; int y,i,n; void main(void) {     y=~x;     i=y+1;  } 

there 2 main ways have done in past. first bit mask use if checking exact same bit(s). example:

#define mask 0x80000000  // return value of "0" means bit wasn't set, "1" means bit was. //      can check many bits want call. int applymask(int number) {     return number & mask; } 

second bit shift, mask (for getting arbitrary bit):

int checkbit(int number, int bitindex) {     return number & (1 << bitindex); } 

one or other of these should looking for. best of luck!