1. fread/fwrite實現復制功能

#include <stdio.h>
#include <stdlib.h>

#define BUFFSIZE  4096

//執行: ./a.out file1 file2
//功能： 將file1的內容讀取出來，寫入file2,即復制 
int main(int argc,char *argv[])
{
    char buffer[BUFFSIZE];
    FILE *pRead,*pWrite; //讀文件指針 寫文件指針 
    int n;

    //檢測是否輸入file1和file2
    if(argc!=3)
    {
        printf(
 
"main option error!\n");
        return -1;
    }

    pRead = fopen(argv[1],"r"); //只讀 文件必須已存在
    if(!pRead)
    {
        printf("fopen argv[1] error!\n");
        return -1;
    }

    pWrite = fopen(argv[2],"w"); //只寫 若文件不存在，則創建
    if(!pWrite)
    {
        printf("fopen argv[2] error!\n");
        
 
return -1;
    }

    //從pRead指向文件讀取字符入buffer
    while( (n= fread(buffer,sizeof(char),sizeof(buffer),pRead))>0 )
    {
        //檢測從buffer寫入pWrite指向文件的字符數，是不是等於讀取字符數
        if( fwrite(buffer,sizeof(char),n,pWrite)!=n )
        {
            printf("fwrite error!\n");
            return -1;
        }
    }

    
 
if(n<0) //fread返回值<0,說明fread讀取失敗
    {
        printf("fread error!\n");
        return -1;
    }

    //復制結束後，要關閉文件
    fclose(pRead);
    fclose(pWrite);

    return 0;
}

fread/fwrite實現復制功能