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，它都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模式打开文件，而不是write模式。

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

此语句以program.bin binary模式打开文件write。此模式表示每次打开文件时，文件的初始内容都将被截断。

您应该使用：

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

有关详细信息，请访问this link

Answer 2

您每次都会覆盖文件的内容，因为您正在使用模式w来编写文件，该文件从头开始重写文件。如果您只想将数据附加到文件的末尾，则应使用模式a，如下所示：

fptr=fopen("program.bin","ab");
//                        ^ Using 'append' mode, rather than 'write' mode.

fprintf用C覆盖其他数据

2 个答案: