什么是与意义QUOT;％ - * S＆QUOT;在格式化字符串 [英] What is the meaning of "%-*.*s" in a printf format string
问题描述
#define FMT "%-*.*s e = %6ld, chars = %7ld, stat = %3u: %c %c %c %c\n"
本宏传递到的printf 功能。是什么％ - *？* S 的意思是
This macro is passed into the printf function. What does %-*.*s mean?
推荐答案
您可以阅读这里的printf手册页：<一href=\"http://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html\">http://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html.但它更像是一个比一个教程法律文本，这将是很难用有限的英语技能理解。
You can read the manual page for printf here: http://pubs.opengroup.org/onlinepubs/009695399/functions/fprintf.html. But it's more like a law text than a tutorial so it will be hard to understand with limited English skills.
我不知道 *。* ，不得不阅读man page自己。这真有趣。让我们先从一个简单的的printf（％S，ABC）。它将打印字符串 ABC 。
I didn't know *.* and had to read the man page myself. It's interesting. Let's start with a simple printf("%s", "abc"). It will print the string abc.
的printf（％8S，ABC）将打印＆NBSP;＆NBSP;＆NBSP;＆NBSP;＆NBSP; ABC（8是最小的字段宽度）。
printf("%8s", "abc") will print " abc" (8 is the minimum "field width").
的printf（％ - 8S，ABC）将打印ABC＆NBSP;＆NBSP;＆NBSP;＆NBSP;＆NBSP; （减号表示在场上左对齐）。
printf("%-8s", "abc") will print "abc " (the minus indicates left alignment in the field).
现在的明星：的printf（％ - * S，8，ABC）将打印相同的。星号表示该字段宽度将作为一个参数的printf传递。这样，就可以以编程方式更改。
Now for the star:
printf("%-*s", 8, "abc") will print the same. The star indicates that the field width will be passed as a parameter to printf. That way it can be changed programmatically.
现在为precision，即：的printf（ - ％* 10S81234567890123）将打印1234567890（以下简称precision是的情况下，最大字段宽度字符串）。
Now for the "precision", that is :
printf("%-*.10s", 8, "1234567890123") will print "1234567890" (the "precision" is the maximum field width in case of strings).
最后的printf（％ - *。*的，8，10，1234567890123）将打印和以前一样，但最大字段宽度作为参数，了。
And finally
printf("%-*.*s", 8, 10, "1234567890123") will print the same as before, but the maximum field width is given as a parameter, too.
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