無法讓我的while循環執行。它會通過並在最後再次請求patientid，然後退出

Question

無法讓我的while循環執行。它經過並要求在再次結束patientid，然後退出

//boolean flag for being in control group 
    isInControlGroup = false; 

    Scanner keyboard = new Scanner (System.in); 
//prompt for patients I.D., import keyboard. 
    System.out.print("Enter Patient id: "); 

//read Patients I.D. 
    patientId = keyboard.nextLine(); 

患者ID必須被隨後a或b 3號。像123A 這是它搞亂：

//finding if patient is a part of the control group 
    while(patientId != null && !patientId.equals("")){ //Test for input in the patientID  string. && !patientId.equals("") 


//Decide if patient is in control group or not 


    if (patientId.charAt(patientId.length()-1)== 'a') 
      isInControlGroup = true; 
    else if(patientId.charAt(patientId.length()-1)== 'b') 
      isInControlGroup = false; 
    else 
     isInControlGroup = false; 

I think it might not be reading the a and b properly.not sure though. 
//prompt for the sex of the patient (M or F). 
    System.out.println("Enter sex (m/f) for patient:"); 


//read the sex of the patient 
    input = keyboard.nextLine(); 
    sex = input.charAt(0);  

//Prompt for total cholesterol, HDL, and triglycerides 
    System.out.println("Enter total cholesterol, HDL, and triglycerides for patient " + patientId + ":"); 

//read total cholesterol, HDL, and triglycerides. 
    totalCholesterol = keyboard.nextInt(); 
    HDL = keyboard.nextInt(); 
    triglycerides = keyboard.nextInt(); 

//Compute LDL value using LDL=totalCholesterol-HDL-triglycerides/5. 
    LDL = totalCholesterol - HDL - triglycerides/ 5; 

//Compute totalChloesterolRatio(decimal division). totalChloesterolRatio=totalChloesterol/HDL 
    totalCholesterolRatio = totalCholesterol/(double)HDL; 
    totalCholesterolRatio= Math.round(totalCholesterolRatio*10);//Use Math.round. 
    totalCholesterolRatio= totalCholesterolRatio/10;//Use 10 to get decimal at tenth spot. 

//Update quantitities to compute averages for aggregate report, using a boolean flag. 
    if(isInControlGroup==true) 
    { 
    controlMembers++;//Increment Counter for control members. 
    controlLdlTotal += LDL; 
    controlRatios += totalCholesterolRatio; 
    } 

    if(isInControlGroup== false) //If isInControlGroup is false, it adds counts to the treatment group. 
    { 
    treatmentMembers++;//Increment counter for treatment members. 
    treatmentLdlTotal += LDL; 
    treatmentRatios += totalCholesterolRatio; 
    } 





//Determine the totalCholesterol classification 
    if (totalCholesterol >= 240) 
    totalChloesterolClassification = "HIGH"; 

    else if (totalCholesterol >= 200) 
     totalChloesterolClassification = "BORDERLINE HIGH"; 

    else if (totalCholesterol < 200) 
     totalChloesterolClassification = "DESIRABLE"; 

//Determine HDL classification 
    switch(sex) 
    { 

    case 'm'://When the sex is male. 
    case 'M': 
     if(HDL<40) 
      hdlClassification="LOW"; 
     else if(HDL<=59) 
      hdlClassification="AVERAGE"; 
     else if(HDL>=60) 
      hdlClassification ="HIGH"; 
     break; 
    case 'w'://When sex is female. 
    case 'W': 
     if(HDL<50) 
      hdlClassification = "LOW"; 
     else if(HDL<=59) 
      hdlClassification="AVERAGE"; 
     else if(HDL>=60) 
      hdlClassification="HIGH"; 
    break; 
    } 
//Determine LDL classification 
    if(LDL >= 160) 
    LDLClassification = "HIGH"; 

    if(LDL >= 130 && LDL <= 159) 
     LDLClassification = "BORDERINE HIGH"; 

    if(LDL >= 100 && LDL <= 129) 
     LDLClassification = "NEAR OPTIMAL"; 

    if(LDL >= 0 && LDL < 100) 
     LDLClassification = "OPTIMAL"; 


//Determine triglycerides classification 
    if (triglycerides >= 200) 
     triglyceridesClassification = "HIGH"; 

     else if (triglycerides >= 199) 
      triglyceridesClassification = "BORDERLINE HIGH"; 

     else if (triglycerides < 150) 
      triglyceridesClassification = "DESIRABLE"; 


//Determine totalChloestrol/HDL Ratio classification 
    if (totalCholesterolRatio >= 5.1) 
     totalCholesterolRatioClassification = "INCREASED RISK"; 

     else if (totalCholesterolRatio >= 3.3) 
      totalCholesterolRatioClassification = "AVERAGE RISK"; 

     else if (totalCholesterolRatio < 3.3) 
      totalCholesterolRatioClassification = "DECREASED RISK"; 


System.out.println("Lipid Profile for Patient "+ patientId); 
System.out.println("Total cholesterol: " + totalCholesterol + " " +  totalChloesterolClassification); 
System.out.println("HDL: "+ HDL+ " " + hdlClassification); 
System.out.println("LDL:" + LDL + " "+ LDLClassification); 
System.out.println("Triglycerides: " + triglycerides + " " + triglyceridesClassification); 
System.out.println("Ratio: " + totalCholesterolRatio + " " + totalCholesterolRatioClassification); 

第二ID後，它退出這一切說明。

patientId=null; 
System.out.print("Enter Patient id: "); 
patientId = keyboard.nextLine(); 
keyboard.nextLine(); 

} //end of loop 

再次提示輸入id，然後退出。

Answer 1

在循環的底部，你有一個額外keyboard.nextLine()