请教：一个写eeprom的问题

这是书上一段往EEprom里写数据的程序

void wirte_eeprom(unsigned char adddress, unsigned char value);
void save_it(unsigned char add,unsigned char dat,unsigned char size)
{
switch(size)
{
case sizeof(float):
write_eeprom(add+3,dat);
write_eeprom(add+2,dat);
case sizeof(long):
write_eeprom(add+1,dat);
case sizeof(char):
write_eeprom(add,dat);
}
}

...
float fance_fraction;
save_it(ee_index, fance_fraction, sizeof(fance_fraction));//函数原型的第二参数是char，按理说fance_fraction不是应该被截成char型吗？那怎么能把4个字节长的float型数据全部存起来呢？

请达人指教！