C语言“fread”函数的用法？

C语言“fread”函数的用法？

C语言“fread”函数的用法为“size_tf read(void *buffer,size_t size,size_t count,FILE *stream)”，其作用是从一个文件流中读数据，读取count个元素，每个元素size字节。

示例1

#include <stdio.h>
#include <process.h>
#include <string.h>
int main()
{
	FILE *stream;
	char msg[]=this is a test;
	char buf[20];
	if ((stream=fopen(dummy.fil,w+))==NULL)
	{
		fprintf(stderr,cannot open output file.\n);
		return 1;
	}
	/*write some data to the file*/
	fwrite(msg,1,strlen(msg)+1,stream);
	/*seek to the beginning of the file*/
	fseek(stream,0,SEEK_SET);
	/*read the data and display it*/
	fread(buf,1,strlen(msg)+1,stream);
	printf(%s\n,buf);
	fclose(stream);
	system(pause);
	return 0;
}

示例2

int main(void)
{
	FILE *stream;
	char list[30];
	int i,numread,numwritten;
	/*open file in text mode:*/
	if ((stream=fopen(fread.out,w+t))!=NULL)
	{
		for (i=0;i<25;i++)
		{
			list[i]=(char)('z'-i);
		}
		/*write 25 characters to stram*/
		numwritten=fwrite(list,sizeof(char),25,stream);
		printf(Wrote %d items\n,numwritten);
		fclose(stream);
	}
	else
		printf(Problem opening the file\n);
        if ((stream=fopen(fread.out,r+t))!=NULL)
        {
			numread=fread(list,sizeof(char),25,stream);
			printf(Number of items read =%d\n,numread);
			printf(Contents of buffer=%.25s\n,list);
			fclose(stream);
        } 
        else
        {
			printf(File Could not be opened\n);
        }
	system(pause);
	return 0;
}

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原文地址：https://www.jb51.cc/csharp/1192648.html