從文件讀取數據時發生無限循環

Question

我正在嘗試從文件中讀取數據。 三行。 我所做的是在下面。 問題是（文件存在）讀取文件時是無限循環。 我觀察到程序直到到達文件末尾才逐行移動。 我的代碼有什么不正確的地方？

碼：

if (desktops == NULL) {
        printf("\n No such file.\n");
    } else{
            printf("\nFile exists. Reading\n");

        while(!feof(desktops)){

            if(numberOfObjects== 0)
            {
                 fscanf(desktops,"%fl %fl %fl %fl %d %s %s %d\n",&height,&length,&width,&processorClock,&idNumberSerial,&processorTypeChars,&nameInNetworkChars,&ID);
                 nameInNetwork = string(nameInNetworkChars);
                 processorType = string(processorTypeChars);
                // nameInNetwork = "test";
                 glowaListyObjektow = new Desktop(height,length,width,processorClock,idNumberSerial,processorType,nameInNetwork,ID);
                 iterator = glowaListyObjektow;


                 iterator->previousObject = NULL;
                 iloscObiektow++;
                 nameInNetwork.clear();
                 processorType.clear();
            }
            else if(numberOfObjects> 0)
            {
                fscanf(desktops,"%fl %fl %fl %fl %d %s %s %d\n",&height,&length,&width,&processorClock,&idNumberSerial,&processorTypeChars,&nameInNetworkChars,&ID);
                nameInNetwork = string(nameInNetworkChars);
                processorType = string(processorTypeChars);
                // nameInNetwork = "test";
                iterator->nextObject = new Desktop(height,length,width,processorClock,idNumberSerial,processorType,nameInNetwork,ID);


                iterator->nextObject->previousObject = iterator;
                iterator = iterator->nextObject;
                iloscObiektow++;
                 nameInNetwork.clear();
                 processorType.clear();
                // nameInNetworkChars = NULL;
            }



            cout<<"reading line"<<endl;
// Here line above is printed infinitely.
        }
            fclose(desktops);
    } 

Answer 1

我看到的問題。

1. 您使用了錯誤的格式， %fl而不是%lf 。
2. 您沒有檢查fscanf是否成功讀取數據。

更改

 fscanf(desktops,"%fl %fl %fl %fl %d %s %s %d\n", &height, &length, &width, &processorClock, &idNumberSerial, &processorTypeChars, &nameInNetworkChars, &ID);

至

 int n = fscanf(desktops,"%lf %lf %lf %lf %d %s %s %d\n", &height, &length, &width, &processorClock, &idNumberSerial, &processorTypeChars, &nameInNetworkChars, &ID);
 if ( n != 8 )
 {
    // Deal with error condition
 }