从方法向主方法获取变量的值

Question

下面有一个程序，我正在调用getTotalPasserian(pm)方法，但在获取用户输入的值时遇到了问题。

do {
            
            /*Menu being called from method and gives 6 options to the user. 
             Chosen option will be stored in "choice" variable.*/
    
    printmenu.menu();
    
    
    choice = sc.nextInt();
    
    //Creating a switch statement for the 6 menu options.
    
    switch (choice) {
    
    
    case 1 :  /* Asks user to input total number of passengers
              and a while loop to check if a positive number input is entered.
              If a negative input is entered the user is asked again to enter a positive entry.
              All inputs are stored in a variable.
              After a positive entry program continues to next question. */
        
             getTotalPassengers(pm);

public static  int getTotolPassengers(int pm) {  
     
      while (pm <= 0) {
        System.out.println("Enter total number of  passengers from Malta :");
        pm = sc.nextInt();
                    
        if (pm <= 0) {
          printpositive.positive ();
          continue;
        } 
     }

    return pm;
}

pm=0、cm=0、pi=0、ci=0、ps=0、cs=0，或者当我试着做pm=gettotalposysers（pm=0)时，它可以工作，但没有向用户显示主菜单printmenu.menu（）；从上面除了system.out.println（“输入来自马耳他的乘客总数：”）；首先从方法中，然后从菜单中。我希望能够在main方法的pm变量中使用变量pm from方法的值。谢谢

Answer 1

您不需要将pm传递到getTotalProsperson()。将pm定义为本地整数变量，并初始化为0。一旦用户输入了有效值，就从函数返回pm。

public static int getTotalPassengers() {
    int pm = 0;
 
    while (pm <= 0) {
        System.out.println("Enter total number of  passengers from Malta :");
        pm = sc.nextInt();                        
        if (pm <= 0)
            printpositive.positive();   // let user know they've entered a bad value
    }

    return pm;
}

然后，在case语句中，使用gettotalpsymperson()。