以下控制字符的含义:
回车 换行 换页
以下控制字符的含义:
回车 换行 换页
当前回答
在老式的纸质打印机终端上,前进到下一行需要两个动作:将打印头移回水平扫描范围的起点(回车)和前进正在打印的纸卷(换行)。
由于我们不再使用纸质打印机终端,这些动作已经无关紧要了,但用来发出信号的字符以各种形式存在。
其他回答
看看维基百科:
基于ASCII或兼容字符集的系统分别使用LF(换行,'\n', 0x0A,十进制10)或CR(回车,'\r', 0x0D,十进制13),或CR后跟LF (CR+LF, 0x0D 0x0A)。这些字符是基于打印机命令的:换行指示一行纸应该从打印机输出,回车指示打印机的回车应返回到当前行的开头。
when I was an apprentice in the Royal Signals many (50) years ago, teletypes and typewriters had "Carriage" with the printing head on them. When you pressed RETURN the Carriage would fly to the left. Hence Carriage Return (CR). You could just return the Carriage, but on mechanical typewriters, you'd use the Lever (much like a tremolo lever on an electric guitar) which would also do the Line Feed. Your next question is why would you not want the line feed? heh heh well in those days to delete characters we'd do a CR then use a Tip-ex-like paper in between the hammerheads and paper and type the same keys to over-write with white ink. Some fancy typewriters had a key you could press. So there you go.
“\n”是换行字符。这意味着结束当前行,并为正在阅读它的任何人转到新的行。
在老式的纸质打印机终端上,前进到下一行需要两个动作:将打印头移回水平扫描范围的起点(回车)和前进正在打印的纸卷(换行)。
由于我们不再使用纸质打印机终端,这些动作已经无关紧要了,但用来发出信号的字符以各种形式存在。
这些是非印刷字符,与“新行”的概念有关。\n是换行。\r是回车。在不同的平台上,相对于有效的新行,它们有不同的含义。在windows中,新行是\r\n。在linux中,\n。在mac中,\r。
实际上,将它们放在任何字符串中,都会对字符串的打印结果产生影响。