C:我怎么知道我正在使用的函数需要什么头文件？

Question

C 语言示例(无 header ):

int main()
{
printf("\nHello World\n");
}

我怎么知道我应该在什么包含 header (例如:#include <stdio.h>)之前？

Answer 1

考虑到您可能无法在线搜索(我猜大多数时候这是显而易见的选择)并且您使用的是 linux 机器，您也可以在手册页中搜索它。
要在手册页中搜索，您可以使用 man -k {search term}

例如printf

$ man -k printf 
asprintf (3)         - print to allocated string
dprintf (3)          - formatted output conversion
fprintf (3)          - formatted output conversion
fwprintf (3)         - formatted wide-character output conversion
printf (1)           - format and print data
printf (3)           - formatted output conversion
snprintf (3)         - formatted output conversion
sprintf (3)          - formatted output conversion
swprintf (3)         - formatted wide-character output conversion
vasprintf (3)        - print to allocated string
vdprintf (3)         - formatted output conversion
vfprintf (3)         - formatted output conversion
vfwprintf (3)        - formatted wide-character output conversion
vprintf (3)          - formatted output conversion
vsnprintf (3)        - formatted output conversion
vsprintf (3)         - formatted output conversion
vswprintf (3)        - formatted wide-character output conversion
vwprintf (3)         - formatted wide-character output conversion
wprintf (3)          - formatted wide-character output conversion
XtAsprintf (3)       - memory management functions

$ man 3 printf
PRINTF(3)                                                                                  Linux Programmer's Manual                                                                                 PRINTF(3)

NAME
       printf, fprintf, dprintf, sprintf, snprintf, vprintf, vfprintf, vdprintf, vsprintf, vsnprintf - formatted output conversion

SYNOPSIS
       #include <stdio.h>

       int printf(const char *format, ...);
       int fprintf(FILE *stream, const char *format, ...);
...