串口傳輸數(shù)據(jù)時，結(jié)構(gòu)體如何轉(zhuǎn)換

typedef?union
{
??float?f;
??unsigned?char?s[4];
}Union_test;

#include?
//共用體
//float?f;//4個字節(jié)
//char?s[4];//4個字節(jié)
typedef?union
{
????float?f;
????unsigned?char?s[4];
}Union_test;
typedef?struct?st
{
????float?f1;
}Struct_test;
void?main(void)
{
????float?a=231.5;
????Union_test?x;
????Struct_test?z;
????x.f?=?a;
????z?=?*(Struct_test?*)(&(x.s));
????printf("z=%.2f\r\n",(double)z.f1);
????printf("End?of?this?programme\r\n");
}

我們可以通過下面的函數(shù)測試是大端存儲還是小端存儲：

void?test(void)
{
????int?a?=?1;
????unsigned?char?*start=&a;
????if(*start?==?1)
????????printf("小端存儲");
????else?if(*start?==?0)
????????printf("大端存儲");
}