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

int right(char *password)
{
    int i,j,z;
    char y[7]="123456";
    for(i=0,j=0;i<6,j<6;i++,j++)
    {
        if(password[i]!=y[j])
            return z=0;
    }
}
   
void DecryptFile(FILE *sfp,FILE *dfp,char *pwd)
{
    char ch;
    int i=1;
    while((ch=fgetc(dfp))!=EOF)
    {
        ch=ch+pwd[i];
        i++;
        fputc(ch,sfp);
    }
}

void OutputFile(FILE *fp)
{
    char ch;
    while((ch=fgetc(fp))!=EOF)
        putchar(ch);
}

int main(int argc,char *argv[])
{
    char *pwd;
    char ch;
    FILE *sfp,*dfp;
    printf("需要解密的文件为:\n");
    puts(argv[1]);
    printf("加密后的文件为:\n");
    puts(argv[2]);
    printf("密码为:\n");
    puts(argv[3]);
    if(right(argv[3])!=0)
    {
    if((dfp=fopen(argv[2],"r"))==NULL)
    {
        printf("无法打开文件 :%s\n",argv[2]);
        exit(0);
    }
    printf("加密后的内容为:\n");
    OutputFile(dfp);
    if((sfp=fopen(argv[1],"w+"))==NULL)
    {
        printf("无法打开文件 :%s\n",argv[1]);
    }
    DecryptFile(sfp,dfp,argv[3]);
    printf("\n解密之后的内容为：\n");
    fseek(sfp,0L,SEEK_SET);
        OutputFile(sfp);
    fclose(sfp);
    fclose(dfp);
    }
    else
        printf("密码错误");
    return 0;
}