putc需要stdout，而puts [英] putc needs stdout, vs puts

问题描述

C历史问题在这里.为什么C函数putc需要第二个参数，如

C history question here. Why does the C function putc require a second parameter like

putc( 'c', stdout ) ;

看跌期权更方便

puts( "a string" ) ;

msvc ++中有一个功能

There is a function in msvc++

putchar( 'c' ) ;

哪种工作方式可能会期望putc起作用.我以为putc的第二个参数是能够将putc定向到文件，但是为此有一个功能fputc.

Which works the way one might expect putc to work. I thought the second parameter of putc was to be able to direct putc to a file, but there is a function fputc for that.

推荐答案

int putc ( int character, FILE * stream );

向流中写入一个字符，并向前移动位置指示器.
因此，它是比putchar
更通用的函数 其他功能可以基于此，例如

Writes a character to the stream and advances the position indicator.
So it is a more generic function than putchar
Other functions can be based on this e.g.

#define putchar(c) putc((c),stdout)  

根据Kernighan的书putc与fputc等效，但是putc可以实现为宏，而putc 可能不得不多次评估其流参数.
我已经读过，据说两者都存在是为了向后兼容，但是不确定这是否有效

According to Kernighan's book putc is equivalent with fputc but putc could be implemented as a macro and putc may have to evaluate its stream argument more than once.
I have read that supposedly that both exist for backward compatibility, but not sure if this is valid

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