如何在不打印尾随换行符的情况下使用printf打印字符串 [英] How to print a string using printf without it printing the trailing newline

问题描述

我正在尝试使用printf()打印一些字符串，但是它们以 null终止，并带有尾随换行符，并且与格式混乱:

I'm trying to print some strings using printf() but they are null terminated having trailing newline and that messes with the formating:

printf("The string \"%s\" was written onto the file \"%s\"", str, fname);

说字符串包含"The Racing car."，文件名是"RandomText1.txt" 打印:

Say the string contains "The Racing car." and the file name is "RandomText1.txt" This prints:

The string "The Racing car.
" was written onto the file "RandomText1.txt
"

但是我希望它仅打印一行:

However I want it to print in just one line:

The string "The Racing car." was written onto the file "RandomText1.txt"

我知道我可以修改字符串以摆脱 null终止符换行符，但我希望有一种可能的方式，在不修改字符串的情况下实现此输出.

I know I can modify the strings to get rid of the null terminator newline but I'd like a way, if possible, to achieve this output without modifying the strings.

有可能吗?

推荐答案

这与null终止符无关. 字符串 必须以空值结尾.

This has nothing to do with the null terminator. a string must be null-terminated.

您在此处遇到尾随换行符(\n)的问题.您必须先剥离该换行符，然后再将字符串传递给printf().

You're facing issues with the trailing newline (\n) here. you have to strip off that newline before passing the string to printf().

最简单的方法[需要修改str "]:您可以使用

Easiest way [requires modification of str]: You can do this with strcspn(). Pseudo code:

str[strcspn(str,"\n")] = 0;

(如果可能)在不修改字符串的情况下实现此输出.

是的，也是可能的.在这种情况下，您需要在printf()中使用length修饰符来限制要打印的数组的长度，例如

Yes, possible, too. In that case, you need to use the length modifier with printf() to limit the length of the array to be printed, something like,

printf("%15s", str);  //counting the ending `.` in str as shown

但是恕我直言，这不是最好的方法，因为必须知道并固定字符串的长度，否则它将无法正常工作.

but IMHO, this is not the best way, as, the length of the string has to be known and fixed, otherwise, it won't work.

一种灵活的情况，

printf("%.*s", n, str);

其中，必须提供n，并且它需要保留要打印的字符串的长度(没有换行符)

where, n has to be supplied and it needs to hold the length of the string to be printed, (without the newline)

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