使用 File IO 和 2Darray 比较 C 语言中的字符串错误 [关闭]

Question

我的程序用于删除数据文件中的记录。我会要求用户输入他要删除的“记录号”。但是，当我使用 strcmp 这个函数比较两个字符串时，它不起作用。

问题：无法使用 strcmp 删除某些记录并将更新的数据放入新文件中

这是我的代码：

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

int main(){
    Del_menu();
    return 0;
}

// function1
int Del_menu() {
    while (1) {
          printf("Please enter a record number you wanted to delete : ");
          Del();
          printf("\nDo u want to delete  other record? Enter 'y' for yes and 
          'n' for no :");
          char ans;
          scanf(" %c", &ans);
          if (ans == 'N' || ans == 'n') {
          break;
          }
    }
}

//function2
int Del(){

        FILE *sfr = fopen("stock.txt", "r"); 
        //just for me getting total number,you can igone this
        char *str;
        int total;
        total=0;
    while (!feof(sfr)){
        str = fgetc(sfr);
        if(str == '\n') {
        total++;
        }
    }
        total = (total/9);
        fclose(sfr);

        FILE *fileptr1, *fileptr2;
        char filename[40] = "data.txt";
        int total = 0;  
        int  total_1 = 0 ,total_2 = 0, i = 0 , temp;

   char itemrecord [40][40];
   char quantity [40][40];
   char weight [40][40];
   char itemname [40][40];
   char catagory [40][40];
   char recipient [40][40];
   char final_destination [40][40];
   char status [40][40];

        fseek(stdin, 0, SEEK_END);
        fflush(stdin);

        i++;
        total--;
        }

        FILE *fileptr1, *fileptr2;
        char filename[40]="stock.txt";

        fileptr1 = fopen(filename, "r");

        char buffer [50];
    while(total_1!=0){

  fgets(recordnum[i],50,fileptr1);
  fgets(itemname[i],50,fileptr1);
  fgets(itemrecord[i],50,fileptr1);
  fgets(catagory[i],50,fileptr1);
  fgets(quantity[i],50,fileptr1);
  fgets(weight[i],50,fileptr1);
  fgets(recipient[i],50,fileptr1);
  fgets(final_destination[i],50,fileptr1);
  fgets(status[i],50,fileptr1);
  fgets(buffer, 50,fileptr1);
        fclose(fileptr1);
        fclose(fileptr2);
        i++;
        total_1--;
  }

        char del_data[41]; //get user input
        fgets(del_data,50,stdin);
        del_data[strlen(del_data) - 1] = '\0';
        printf("\nyou have entered :%s\n", del_data);

        printf("\nRecord in file before delete:\n");
        printf("Total record: %d\n",total);

        i=0;
    while(total_2!=0){

       printf("%s%s%s%s%s%s%s%s%s\n",recordnum[i],itemrecord[i],quantity[i],
       weight[i],itemname[i], catagory[i],recipient[i],
       final_destination[i],status[i]);
       i++;
       total_2--;
    }

       rewind(fileptr1);

       fseek(stdin, 0, SEEK_END);
       fileptr2 = fopen("copy.c", "w");  //stored the data after deleted
       total_3=total_3 -1;

       i=0; 
    while(total!=0){

       if ( strcmp(recordnum[i],del_data) != 0){
       printf("%s",recordnum[i]); //for me checking is it successful              

       fprintf(fileptr2,"%s%s%s%s%s%s%s%s%s\n",recordnum[i],itemrecord[i],
       quantity[i],weight[i],itemname[i], catagory[i],recipient[i],
       final_destination[i],status[i]);

       i++; total--;}
            }


remove(filename);
// rename the file copy.c to original name
rename("copy.c", filename);
} // end of function 2

结果：

Please enter a record runber you want to delete: 1001

You enterd: 1001

Record in file before deleted:
Total:3
1001
Orange Laptop Computer DX5
235524
Electronics
1
1.8 kg
Chan 
Mong Kok
Delivery

1002
Japanese Garden Pear Gift Box
300522
Food
2
4.2 kg
Cheung 
Yuen Long
Arrival

1003
Koppo Badminton Racket GPX-15
77524
Fashion
3
0.6 kg
Lee Siu Yu
Fortress Hill
Warehouse

1001 // not exist after i finish this code
1002 // just for I debugging now
1003 // here is my problem* mean that cannot delete record successful

DO you want to delete other record?Enter'y' for yes, 'n' for no: n

Answer 1

当您读取用户的选择时，您会小心删除fgets() 存储在缓冲区中的尾随换行符，但您不会对读取到数组中的数据应用相同的处理。您的文件似乎将每个字段放在单独的行上，因此您读入数组的数据中确实有换行符。因此比较失败，因为字符串确实不同。

最简单的解决方案是停止从用户输入中删除尾随换行符。这段代码还有很多其他问题，但做出改变至少应该让它在你询问的方面发挥作用。