文件的复制

#include <string.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#define BUFFER_SIZE 1024 


int main(int argc,char **argv) 
{ 
FILE *from_fd;
FILE *to_fd; 
long file_len=0;
char buffer[BUFFER_SIZE]; 
char *ptr; 

/*判断入参*/
if(argc!=3) 
{ 
printf("Usage:%s fromfile tofile\n",argv[0]); 
exit(1); 
} 


/* 打开源文件 */ 
if((from_fd=fopen(argv[1],"rb"))==NULL) 
{ 
printf("Open %s Error\n",argv[1]); 
exit(1); 
} 


/* 创建目的文件 */ 
if((to_fd=fopen(argv[2],"wb"))==NULL) 
{ 
printf("Open %s Error\n",argv[2]); 
exit(1); 
} 


/*测得文件大小*/
fseek(from_fd,0L,SEEK_END);
file_len=ftell(from_fd);
fseek(from_fd,0L,SEEK_SET);
printf("from file size is=%d\n",file_len);


/*进行文件拷贝*/
while(!feof(from_fd)) 
{ 
fread(buffer,BUFFER_SIZE,1,from_fd);
if(BUFFER_SIZE>=file_len)
{
fwrite(buffer,file_len,1,to_fd);
}
else 
{
fwrite(buffer,BUFFER_SIZE,1,to_fd);
file_len=file_len-BUFFER_SIZE;
}
memset(buffer, 0, BUFFER_SIZE);
// // bzero(buffer,BUFFER_SIZE); //清零
} 
fclose(from_fd); 
fclose(to_fd); 
exit(0); 
}