c - fprintf覆盖C中的其他数据

Question

我正在尝试将 struct employee 写入文件，但无论我输入 case 语句多少次，它只会写入最近输入的一个。

    case '1':
    {
        fptr=fopen("program.bin","wb");

        if(fptr==NULL)
        {
            printf("Error!");
            exit(1);
        }

        printf("\nA is: %d\n",a);

        printf("\nPlease enter the employee's ID: ");
        scanf("%s",&employee[a].ID);
        fprintf(fptr,"Employees ID number:     %s\r\n",employee[a].ID);

        printf("\nPlease enter the employee's first name: ");
        scanf("%s",&employee[a].firstname);
        fprintf(fptr,"Employees first name:    %s\r\n",employee[a].firstname);

        printf("\nPlease enter the employee's Surname: ");
        scanf("%s",&employee[a].surname);
        fprintf(fptr,"Employees surname:       %s\r\n",employee[a].surname);

        printf("\nPlease enter the employee's Home address: ");
        scanf("%s",&employee[a].address);
        fprintf(fptr,"Employees address is:    %s\r\n",employee[a].address);

        printf("\nPlease enter the employee's department number: ");
        scanf("%s",&employee[a].department);
        fprintf(fptr,"Employees department is: %s\r\n",employee[a].department);

        printf("\nPlease enter the employee's duration: ");
        scanf("%s",&employee[a].duration);
        fprintf(fptr,"Employees duration is:   %s\r\n",employee[a].duration);

        a++;

        fclose(fptr);

        goto CASE; 
     }

Answer 1

以append 模式而非write 模式打开文件。

fptr=fopen("program.bin","wb");

此语句以binary write 模式打开文件program.bin。这种模式意味着每次打开文件时，文件的初始内容都会被截断。

你应该使用:

fptr=fopen("program.bin","ab"); 以append 模式打开文件。

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