pixel.b.bit2=1;

#include <stdio.h>
 
typedef struct TreintaydosBits {
    unsigned bit1 : 1;
    unsigned bit2 : 1;
    unsigned bit3 : 1;
    unsigned bit4 : 1;
    unsigned bit5 : 1;
    unsigned bit6 : 1;
    unsigned bit7 : 1;
    unsigned bit8 : 1;
    unsigned bit9 : 1;
    unsigned bit10: 1;
    unsigned bit11: 1;
    unsigned bit12: 1;
    unsigned bit13: 1;
    unsigned bit14: 1;
    unsigned bit15: 1;
    unsigned bit16: 1;
} TreintaydosBits;
 
typedef union CuatroBytes {
    short n;
    TreintaydosBits b;
} CuatroBytes;
 
int main(){
    CuatroBytes cb;
    cb.n=0;
    cb.b.bit3 = 1;
    printf("%d",cb.n);
}