#include
     
      #include
      
       #include
       
         void main(){FILE *fp1=NULL;FILE *fp2=NULL; char ch; int i=0; char str[6]="abcde"; char strl[1000];  fp1=fopen("1.txt","w"); if(fp1 == NULL) {  perror(" open 1.txt");  //exit( EXIT_FAILURE ); } ch=getchar();fputc(ch,fp1);fputs(str,fp1);printf("%c",ch);fclose(fp1);fp1=fopen("1.txt","r");fp2=fopen("2.txt","w");// while(!feof(fp1))   while(fp1!='\0') will die for(i=0;i<7;i++) {   ch=fgetc(fp1);   fputc(ch,fp2);   putchar(ch); } strl=fp1; // srtcpy(str,fp2);  waring  printf("%s\n",str);fclose(fp1);fclose(fp2);}
       
      
     

注：虚拟机实现  文件打开方式决定后续文件操作