C语言fgets函数按行读取文件

fgets, fgetws
Get a string from a stream.C语言没有像C++、Python语言的getline()函数，无法读取文件的某一行。然而，C语言有fgets()函数，该函数返回string类型，关键是该函数遇到换行符或EOF，则读取结束。利用这一特点，我们可以设置n为适当的缓冲区大小，即可以实现按行读取。

char *fgets( char *string, int n, FILE *stream );
wchar_t *fgetws( wchar_t *string, int n, FILE *stream );

Function Required Header Compatibility 
fgets ANSI, Win 95, Win NT 
fgetws or ANSI, Win 95, Win NT 

For additional compatibility information, see Compatibility in the Introduction.

Libraries

LIBC.LIB Single thread static library, retail version 
LIBCMT.LIB Multithread static library, retail version 
MSVCRT.LIB Import library for MSVCRT.DLL, retail version 


Return Value

Each of these functions returns string. NULL is returned to indicate an error or an end-of-file condition. Use feof or ferror to determine whether an error occurred.


Parameters

string
Storage location for data

n
Maximum number of characters to read

stream
Pointer to FILE structure

Remarks

The fgets function reads a string from the input stream argument and stores it in string. fgets reads characters from the current stream position to and including the first newline character, to the end of the stream, or until the number of characters read is equal to n – 1, whichever comes first. The result stored in string is appended with a null character. The newline character, if read, is included in the string. 

fgets is similar to the gets function; however, gets replaces the newline character with NULL. fgetws is a wide-character version of fgets. 

fgetws reads the wide-character argument string as a multibyte-character string or a wide-character string according to whether stream is opened in text mode or binary mode, respectively. For more information about using text and binary modes in Unicode and multibyte stream-I/O, see Text and Binary Mode File I/O and Unicode Stream I/O in Text and Binary Modes.

e.g:

#include "StaticLib.h"
#include "stdio.h"
#include "string.h" 

bool fnShow()
{
	char cFileName[] = "..\\StaticLib\\StaticLib.h";
	char cFind[] = "extern";
	char cLine[1024];
	int iBuff = 1024;
    FILE *fp;
	fp = fopen(cFileName,"r");
	if(NULL == fp)
	{
		printf("打开文件失败！\n");
		return false;
	}
	while(!feof(fp))
	{
		fgets(cLine,iBuff,fp);
		if(strstr(cLine,cFind))
		{
		    printf("%s",cLine);
		}
	}

	fclose(fp);
	return true;
}