如果不期望答案，我会将这段代码返回到程序的开头。
...
else // returns to start for unsatisfactory
{
System.out.println();
System.out.println();
System.out.println("Check your spelling and try again");
main (args);
}
...
然而，当我输入不同的单词然后再次通过并输入预期的单词时，程序会输出两个不同的结果
<小时/> 目前的薪水：100.00美元
筹集金额：$ 4.00
你的新工资：104.00美元
目前的薪水：100.00美元
加注金额：$ 0.00
您的新薪水：$ 100.00
我尝试使用else if语句来消除它作为一个原因，但它导致了同样的事情。
import java.util.Scanner;
import java.text.NumberFormat;
public class Salary {
public static void main (String[] args) {
double currentSalary; // employee's current salary
double raise = 0.0; // amount of the raise
double newSalary; // new salary for the employee
String rating; // performance rating
Scanner scan = new Scanner(System.in);
System.out.print ("Enter the current salary: ");
currentSalary = scan.nextDouble();
System.out.print ("Enter the performance rating (Excellent, Good, or Poor): ");
rating = scan.next();
// Computes raise with if-else
if ((rating.equals("Excellent")) || (rating.equals("excellent"))) {
// calculates raise for excellent
raise = .06 * currentSalary;
}
else if ((rating.equals("Good")) || (rating.equals("good"))) {
// calculates raise for good
raise = .04 * currentSalary;
}
else if ((rating.equals("Poor")) || (rating.equals("poor"))) {
// calculates raise for poor
raise = .015 * currentSalary;
}
else {
// returns to start for unsatisfactory
System.out.println();
System.out.println();
System.out.println("Check your spelling and try again");
main (args);
}
newSalary = currentSalary + raise;
// Print the results
NumberFormat money = NumberFormat.getCurrencyInstance();
System.out.println();
System.out.println("Current Salary: " + money.format(currentSalary));
System.out.println("Amount of your raise: " + money.format(raise));
System.out.println("Your new salary: " + money.format(newSalary));
System.out.println();
}
}
答案 0 :(得分：2)
这是因为当你没有获得预期的输入时，你递归地调用main（这不被认为是好的练习BTW）。输入（第二次）预期输入后，必须仍然执行初始main的剩余部分，然后使用0.0的raise，因为输入无效。
针对您的问题的实用解决方案可能是避免递归调用main并将其换行，例如像这样的循环中的输入验证
...
System.out.print ("Enter the performance rating (Excellent, Good, or Poor): ");
while (true) {
rating = scan.next();
if ((rating.equals("Excellent")) || (rating.equals("excellent")))
{
raise = .06 * currentSalary; break;
}
else if ((rating.equals("Good")) || (rating.equals("good")))
{
raise = .04 * currentSalary; break;
}
else if ((rating.equals("Poor")) || (rating.equals("poor")))
{
raise = .015 * currentSalary; break;
}
else
{
System.out.println();
System.out.println();
System.out.println("Check your spelling and try again");
}
}
...
答案 1 :(得分：1)
你对main()＆＃34发出的（第二次）电话;结束＆＃34;然后回到第一个＆＃34;通过启动程序调用的那个。
因此，第一批结果来自您对main()的显式调用。第二个地段是从那个电话结束时开始，然后你回到你打电话的地方。
不建议递归调用main()。你应该在main（）中使用while循环。即在您知道输入有效之前继续询问输入，然后实际使用它。
答案 2 :(得分：1)
您致电main (args);后仍未返回，因此您的计划的每次迭代都会继续。
您应该在return;
main (args);
{
System.out.println();
System.out.println();
System.out.println("Check your spelling and try again");
main (args);
return;
}
编辑：正如John3136所指出的那样，你也不应该递归地调用main (args)。
答案 3 :(得分：0)
你不应该递归地调用main。你应该使用do while循环来更新代码并且它工作正常。
import java.util.Scanner;
import java.text.NumberFormat;
public class Salary {
public static void main (String[] args) {
double currentSalary; // employee's current salary
double raise = 0.0; // amount of the raise
double newSalary; // new salary for the employee
String rating; // performance rating
boolean flag=false; // to check input
Scanner scan = new Scanner(System.in);
do{
System.out.print ("Enter the current salary: ");
currentSalary = scan.nextDouble();
System.out.print ("Enter the performance rating (Excellent, Good, or Poor): ");
rating = scan.next();
// Computes raise with if-else
if ((rating.equals("Excellent")) || (rating.equals("excellent"))) // calculates raise for excellent
{
raise = .06 * currentSalary;
flag=true;
}
else if ((rating.equals("Good")) || (rating.equals("good"))) // calculates raise for good
{
raise = .04 * currentSalary;
flag=true;
}
else if ((rating.equals("Poor")) || (rating.equals("poor"))) // calculates raise for poor
{
raise = .015 * currentSalary;
flag=true;
}
else // returns to start for unsatisfactory
{
System.out.println();
System.out.println();
System.out.println("Check your spelling and try again");
flag=false;
}
}while(!flag);
newSalary = currentSalary + raise;
// Print the results
NumberFormat money = NumberFormat.getCurrencyInstance();
System.out.println();
System.out.println("Current Salary: " + money.format(currentSalary));
System.out.println("Amount of your raise: " + money.format(raise));
System.out.println("Your new salary: " + money.format(newSalary));
System.out.println();
}
}
答案 4 :(得分：0)
您可能想要考虑另一种方法。如果输入无效或尝试修复它，请终止问题。以下示例适用于“修复”方法，
public class Salary {
public static void main(String[] args) {
IPM ipm;
if (verify(args)) {
ipm = new IPM(args);
} else {
Scanner scan = new Scanner(System.in);
String[] update;
do {
update = repair(scan);
} while (!verify(update)); // You may want a loop count as well...
ipm = new IPM(update);
}
ipm.print();
}
public static boolean verify(String[] s) {
return IPM.verify(s);
}
public static String[] repair (Scanner s) {
// Request new input and store it in an array of strings.
// This method does not validate the input.
}
}
public class IPM {
double currentSalary;
double raise = 0.0;
double newSalary;
String rating;
IPM(String[] input) {
// Set attributes of IPM.
}
public static boolean verify(String[] s) {
//Determine if the input is valid.
}
public void print() {
// Print IPM object.
}
}
请注意从工资中调用IPM.verify()。这应该是IPM责任的一部分，因为薪水不需要了解主要内容。此外，课程IPM可能会更改，对IPM.verify()的调用也不会要求所有验证IPM的课程也会发生变化。