是否有指定如何字符串的字符打印出来用printf（）的方法吗？ [英] Is there a way to specify how many characters of a string to print out using printf()?

问题描述

是否有指定字符串的多少个字符打印出来（类似于小数位在整数）的方式

Is there a way to specify how many characters of a string to print out (similar to decimal places in ints)

printf ("Here are the first 8 chars: %s\n", "A string that is more than 8 chars");

想它打印：这是第一个8位字符：一个字符串

Would like it to print: "Here are the first 8 chars:A string"

推荐答案

的基本方法是：

printf ("Here are the first 8 chars: %.8s\n", "A string that is more than 8 chars");

另外，往往更有用，方法是：

The other, often more useful, way is:

printf ("Here are the first %d chars: %.*s\n", 8, 8, "A string that is more than 8 chars");

在这里，您指定的长度作为一个int参数的printf（），它把对*的格式要求从参数获得的长度。

Here, you specify the length as an int argument to printf(), which treats the '*' in the format as a request to get the length from an argument.

您也可以使用符号：

printf ("Here are the first 8 chars: %*.*s\n",
        8, 8, "A string that is more than 8 chars");

这也是类似于％8.8S符号，但同样可以让你在运行时指定最小和最大长度 - 更真实地像一个场景：

This is also analogous to the "%8.8s" notation, but again allows you to specify the minimum and maximum lengths at runtime - more realistically in a scenario like:

printf("Data: %*.*s Other info: %d\n", minlen, maxlen, string, info);

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