我把程序简化了下，留下一个最大的问题
还是刚才那个读取文档的内容
文档里的内容如下：
wu        xu             82790229       Yyan       meng           82790389       Nli        ming           82780564       Yli        ming           82780564       N
有点乱，每条记录总共四个字段，到大写的N或Y结束。

读取的代码如下

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

typedef struct
{
    char firstName[10];
    char lastName[15];
    char telNum[15];
    char tag;
}Customer;

Customer customer;
FILE *fp1;

void loadCustomer();

int main( void )
{
    int choice;

    printf( "\n请选择服务选项！\n"
                "0--退出系统\n"
                "1--装载客户信息\n"
                 );
    scanf( "%d", &choice );
    
    while(1)
    {
        switch( choice )
        {
        case 0:
            printf( "\n成功退出系统！\n" );
            exit(1);

        case 1:
            loadCustomer();     //装载客户信息
            break;

        default:
             printf( "\n输入错误，请重新输入\n" );
            break;
        }

        printf( "\n请选择服务选项！\n"
                "0--退出系统\n"
                "1--装载客户信息\n"
                );
        scanf( "%d", &choice );
    }

    return 0;
}

void loadCustomer()    //装载文件内容
{
    Customer cus;

    fp1 = fopen( "customer.txt", "r" );

    if( !fp1 )
    {
        printf( "文件无法打开！" );
        exit(1);
    }

    while(1)
    {
        if( !fread( &cus, sizeof( Customer ), 1, fp1 ) )
            break;

        cus.telNum[9] = '\0';
        cus.firstName[10] = '\0';
        cus.lastName[15] = '\0';

        printf( "%s %s %s %c\n", cus.telNum, cus.firstName, cus.lastName );
    }

    printf( "\n客户资料装载成功\n" );

    fclose( fp1 );
}

读取总是失败。没办法了，超出个人能力之外了，往高手帮忙解决！不胜感激。。。

使用限定宽度的fscanf()函数读入，前面三个是%s，最后一个是%c，每次一条记录。

#include<stdio.h>
#include<stdlib.h>
typedef struct Customer
{
    char firstName[10];
    char lastName[15];
    char telNum[15];
    char tag;
}Customer;
Customer customer;
FILE *fp1;
void loadCustomer();
int main( void )
{
    int choice;
    while(1)
    {
        printf( "\n请选择服务选项！\n"
                "0--退出系统\n"
                "1--装载客户信息\n");
        scanf( "%d", &choice );
        getchar();
        switch( choice )
        {
        case 0:
            printf( "\n成功退出系统！\n" );
            exit(1);
       
        case 1:
            loadCustomer();     //装载客户信息
            break;
       
        default:
            printf( "\n输入错误，请重新输入\n" );
            break;
        }
    }

    return 0;
}
void loadCustomer()    //装载文件内容
{
    Customer cus;

    fp1 = fopen( "customer.txt", "r" );

    if( !fp1 )
    {
        printf( "文件无法打开！" );
        exit(1);
    }

    while(1)
    {
/*        if( !fread( &cus, sizeof( Customer ), 1, fp1 ) )
            break;
   
        cus.telNum[9] = '\0';
        cus.firstName[14] = '\0';
        cus.lastName[14] = '\0';
*/
        if (fscanf(fp1, "%s%s%s %c", cus.telNum, cus.firstName, cus.lastName, &cus.tag) == EOF)    break;
        printf( "%-10s%-15s%-15s\n", cus.telNum, cus.firstName, cus.lastName );
    }
    printf( "\n客户资料装载成功\n" );

    fclose( fp1 );
}

有个函数你可以试下
strtok_s();