union in C

#include <stdio.h>typedef union { unsigned int Ax; struct AX { unsigned int AL:16; unsigned int AH:16; }sAX;}example;int main(void){example a;a.Ax = 0xAFAFBEBE;int i = a.sAX.AH;printf("AX = 0x%X, AH = 0x%X, AL = 0x%X/n", a.Ax, a.sAX.AH, a.sAX.AL);return 0;}

 

AX = 0xAFAFBEBE

AH = 0xAFAF

AL =  0xBEBE

 

底层开发应用较多