Question

我想读取用户输入并验证它是否与“user.txt”记录匹配，如果匹配则会提示用户输入错误消息，但scanf读取的数据将始终变为随机号码，这是代码。我的英语是英语，因为我不是英语母语人士

                int day,month,year;
                char name[15];


                printf("Enter your name\n");
                scanf(" %[^\n]s",name);
                printf("Enter you birthday(dd/mm/yyyy)\n");
                scanf("%d%*[-/]%d%*[-/]%d",&day,&month,&year);
                printf("Enter your contact number (60-)\n");
                scanf("%d",&contactNumber);
                printf("Enter your postcode\n");
                scanf("%d",&postcode);

                char x [30];
                int y,z,w,d;
                int duplicateContactNum [15];
                int checkSentinel=0;

                filepointer=fopen("user.txt","r");
                if(filepointer==NULL){
                //Not exist,Print exception message
                printf("Exception Occur: Error writing text into the text file");

                }
                while(!feof(filepointer))
                {
                    fscanf(filepointer,"%s;%d/%d/%d;%d;%d\n",x,&y,&z,&w,&duplicateContactNum,&d);
                    if(strcmp(contactNumber,duplicateContactNum)==0)
                    {
                        checkSentinel++;
                        break;
                    }

                }
                if(checkSentinel!=0)
                {
                    rewind(filepointer);
                    printf("You have entered a duplicated entry\n");
                    fclose(filepointer);
                }
                else
                {
                    rewind(filepointer);
                    fclose(filepointer);
                    filepointer=fopen("user.txt","a");
                    fprintf(filepointer,"%s;%d/%d/%d;%d;%d\n",name,day,month,year,contactNumber,postcode);
                    fclose(filepointer);
                }

Answer 1

初始格式字符串中有一个错误，并且您没有测试printf("Enter your name\n"); if (1 != scanf(" %[^\n]",name)) { // no s after [] format fprintf(stderr, "Error reading name\n"); return 1; } printf("Enter you birthday(dd/mm/yyyy)\n"); if (3 != scanf("%d%*[-/]%d%*[-/]%d",&day,&month,&year)) { ... } printf("Enter your contact number (60-)\n"); if (1 != scanf("%d",&contactNumber)) { ... } printf("Enter your postcode\n"); if (1 != scanf("%d",&postcode)) { ... }调用的返回值，因此所有返回错误但您没有收到警告。

C5:H558

请记住：始终测试输入功能

如何使用fscanf从文件中读取并使用用户输入查找匹配的记录

1 个答案: