原型是：char *fgets(char *s, int n, FILE *stream);

從文件指針stream中讀取n-1個字符，存到以s為起始地址的空間里，直到讀完一行，如果成功則返回s的指針，否則返回NULL。

例如：一個文件是hello,world，

用fgets(str1,4,file1); ?

執行后str1="hel"，讀取了4-1=3個字符.

而如果用而如果用fgets(str1,23,file1);

則執行str1="hello,world"，讀取了一行(包括行尾的'\n',并自動加上字符串結束符'\0')。

The?fgets?function reads a string from the input?stream?argument and stores it in?str.?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?str?is appended with a null character. The newline character, if read, is included in the string. ? ----from MSDN

DEMO1:

[cpp]?view plaincopy

#include?<stdio.h>??

int?main(void)??

{??

????FILE?*stream;??

????char?line[23];??

????if?(fopen_s(&stream,"abc.txt","r")==0)???//?hello,world??

????{??

????????if?(fgets(line,4,stream)?==?NULL)??

????????{??

????????????printf("fgets?error?\n");??

????????}??

????????else??

????????{??

????????????printf("%s\n",line);??

????????????//printf("len?is?%d\n",strlen(line));??

????????}??

????????fclose(stream);??

????}??

??????

????system("pause");??

????return?0;?????

}??

DEMO2:

[cpp]?view plaincopy

int?main()??

{??

????FILE?*stream;??

????char?string[]="This?is?a?test";??

????char?msg[20];??

????/*w+打開可讀寫文件，若文件存在則文件長度清為零，即該文件內容會消失。若文件不存在則建立該文件。*/??

????stream=fopen("abc.txt","w+");?/*open?a?file?for?update*/??

????fwrite(string,strlen(string),1,stream);?/*write?a?string?into?the?file*/??

????fseek(stream,0,SEEK_SET);??/*seek?to?the?start?of?the?file*/??

????fgets(msg,strlen(string)+1,stream);??

????printf("%s",msg);??

????fclose(stream);??

????system("pause");??

????return?0;??

}??

【FROM MSDN && 百科】

總結

以上是生活随笔為你收集整理的C语言fgets函数了解的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。