关于c语言中逗号表达式
看到有些代码中喜欢用逗号表达式:
如:
if (dlrate < 1024.0)
*units = 0;
else if (dlrate < 1024.0 * 1024.0)
*units = 1, dlrate /= 1024.0;
else if (dlrate < 1024.0 * 1024.0 * 1024.0)
*units = 2, dlrate /= (1024.0 * 1024.0);
else
/* Maybe someone will need this, one day. */
*units = 3, dlrate /= (1024.0 * 1024.0 * 1024.0);
请问这么用逗号表达式的意义是什么?