c - 成员(member)身份识别

Question

char membership[10],memberID[10];
int c;
float AfterDiscount;

printf("\nEnter Your Membership ID to get 5 percent discount: ");
scanf(" %s",&memberID);
member=fopen("Membership.txt","r");
fgets(membership,10,member);
    if(strcmp(membership,memberID)==0)
        {
        AfterDiscount=final*0.95;
        printf("Your final price after 5 percent discount is RM%6.2f",AfterDiscount);
        printf("Thank you to come again, our honour member.");
        fclose(member);
        return AfterDiscount;
        }

printf("The Member ID is not exist. Please kindly contact the adminstrator, 03-XXXXXXX\n");
fclose(member);
return 0;

我想确定是否存在以“B123456789”模式形成的成员资格。我创建了一个成员资格列表并命名为“Membership.txt”。但即使我输入了有效的成员(member) ID，似乎也不起作用。

Answer 1

您调用fgets最多会读取 10 - 1 = 9 个字符，这意味着您读取的 10 个字符 ID 将丢失最后一个字符。此外，您的字符串长度仅足以容纳 9 个字符 + \0 终止符。

更改:

char membership[10],memberID[10];

至:

char membership[11],memberID[11];

并更改:

fgets(membership,10,member);

至:

fgets(membership,sizeof(membership),member);