fwrite()函數----write data to a stream

原型：

size_t?fwrite(const void* buffer, size_t?size, size_t count, FILE* stream);

注意：這個函數以二進制形式對文件進行操作，不局限于文本文件

demo:

[cpp]?view plaincopy

#include?<stdio.h>??

#include?<process.h>??

typedef?struct???

{??

????int?i;??

????char?ch;??

}mystruct;??

int?main()??

{??

????FILE?*stream;??

????mystruct?s;??

????/*wb只寫打開或新建一個二進制文件；只允許寫數據。*/??

????if?((stream=fopen("test.$$$","wb"))==NULL)??

????{??

????????fprintf(stderr,"cannot?open?output?file.\n");??

????????return?1;??

????}??

????s.i=0;??

????s.ch='A';??

????fwrite(&s,sizeof(s),1,stream);??

????fclose(stream);??

????stream=NULL;??

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

????return?0;??

}??

demo2:

[cpp]?view plaincopy

#include?<stdio.h>??

int?main()??

{??

????FILE?*pFile=NULL;??

????char?buffer[]={'x','y','z'};??

????pFile=fopen("myfile.bin","wb");??

????fwrite(buffer,sizeof(buffer),1,pFile);??

????fclose(pFile);??

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

????return?0;??

}??

demo3:

[cpp]?view plaincopy

#include?<stdio.h>??

#include?<process.h>??

int?main()??

{??

????FILE?*fp=NULL;??

????char?msg[]="file?content";??

????char?buf[20];??

????fp=fopen("c:\\a.txt","w+");????//二級目錄會不成功??

????if?(NULL==fp)??

????{??

????????printf("The?file?doesn't?exist!\n");??

????????getchar();??

????????getchar();??

????????return?-1;??

????}??

????fwrite(msg,strlen(msg),1,fp);???//把字符串內容寫入到文件??

????fseek(fp,0,SEEK_SET);???????????//定位文件指針到文件首位置??

????fread(buf,strlen(msg),1,fp);????//把文件讀入到緩存??

????buf[strlen(msg)]='\0';??????????//刪除緩存內多余空間??

????printf("buf=%s\n",buf);??

????printf("strlen(buf)?=?%d\n",strlen(buf));??

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

????return?0;??

}??

總結

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