java中无法解决的错误，是否有任何修复？
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这是我遇到的错误，我似乎无法弄清楚如何解决。我正在尝试这样做，以便一旦完成计算，程序就会询问您是否要再次执行。
线程“主”中的异常java.lang.Error：未解决的编译问题：重试无法解决是，无法解析为变量
我的代码（不要判断，这是我在Java中的第一个程序）：
package calculatorpls;
import java.util.Scanner;
public class calc {
public static void main(String[]Args)
{
do {
Scanner num = new Scanner(System.in);
System.out.println("Please enter the first number."+"
");
int no1 = num.nextInt();
System.out.println("
"+"The number you have entered is "+no1+"."+"
"+"
"+"Please enter the second number now."+"
");
int no2 = num.nextInt();
System.out.println("
"+"The number you have entered is "+no2+"."+"
"+"
"+"Please choose what you would like to do from the following options:"+"
"+
"1)Addition"+"
"+"2}Subtraction(1st Number-2nd Number)"+"
"+"3)Subtraction(2nd Number-1st Number)"+"
"+"4)Multiplication"+"
"+"5)Division(1st Number divided by 2nd Number)"+"
"+"6)Division(2nd Number divided by 1st Number)"
+ ""+"
"+"7)Multiply by an exponent(1st Number)"+"
"+"8)Multiply by an exponent(2nd Number)"+"
"+"
"+"Type any number from 1-8 to select your option."+"
");
//String Addition;
//String Subtraction(1st Number-2nd Number);
//String Subtraction(2nd Number-1st Number);
//String Multiplication;
//String Division(1st Number divided by 2nd Number);
//String Division(2nd Number divided by 1st Number);
//String Multiply by an exponent(1st Number);
//String Multiply by an exponent(2nd Number);
int choice = num.nextInt();
System.out.println("
"+"You have chosen "+choice +"
");
switch (choice)
{
case 1:
float addition = no1+no2;
System.out.println("
"+ addition);
break;
case 2:
float subtraction1 = no1-no2;
System.out.println("
"+ subtraction1);
break;
case 3:
float subtraction2 = no2-no1;
System.out.println("
"+ subtraction2);
break;
case 4:
float multiplication = no1*no2;
System.out.println("
"+ multiplication);
break;
case 5:
double division1 = no1/no2;
System.out.println("
"+ division1);
break;
case 6:
double division2 = no2/no1;
System.out.println("
"+ division2);
break;
case 7:
System.out.println("
"+ "Please enter the power."+"
");
int exponent = num.nextInt();
double exponent1 = (int) Math.pow(no1, exponent);
System.out.println("
"+ exponent1);
break;
case 8:
System.out.println("
"+ "Please enter the power."+"
");
int exponenttwo = num.nextInt();
double exponent2 = (int) Math.pow(no2, exponenttwo);
System.out.println("
"+ exponent2);
break;
default:
System.out.println("
"+ "There isnt any such option matching your entry!"+"
");
break;
}
System.out.println("
"+ "Would you like to perform more calculations? Respond with yes or no."+"
");
String retry = num.nextLine();
String again = "yes";
}while(retry.equalsIgnoreCase(again));
}
}
答案
我为您修复了它。
String retry;
String again;
do {
Scanner num = new Scanner(System.in);
System.out.println("Please enter the first number."+"
");
int no1 = num.nextInt();
System.out.println("
"+"The number you have entered is "+no1+"."+"
"+"
"+"Please enter the second number now."+"
");
int no2 = num.nextInt();
System.out.println("
"+"The number you have entered is "+no2+"."+"
"+"
"+"Please choose what you would like to do from the following options:"+"
"+
"1)Addition"+"
"+"2}Subtraction(1st Number-2nd Number)"+"
"+"3)Subtraction(2nd Number-1st Number)"+"
"+"4)Multiplication"+"
"+"5)Division(1st Number divided by 2nd Number)"+"
"+"6)Division(2nd Number divided by 1st Number)"
+ ""+"
"+"7)Multiply by an exponent(1st Number)"+"
"+"8)Multiply by an exponent(2nd Number)"+"
"+"
"+"Type any number from 1-8 to select your option."+"
");
//String Addition;
//String Subtraction(1st Number-2nd Number);
//String Subtraction(2nd Number-1st Number);
//String Multiplication;
//String Division(1st Number divided by 2nd Number);
//String Division(2nd Number divided by 1st Number);
//String Multiply by an exponent(1st Number);
//String Multiply by an exponent(2nd Number);
int choice = num.nextInt();
System.out.println("
"+"You have chosen "+choice +"
");
switch (choice)
{
case 1:
float addition = no1+no2;
System.out.println("
"+ addition);
break;
case 2:
float subtraction1 = no1-no2;
System.out.println("
"+ subtraction1);
break;
case 3:
float subtraction2 = no2-no1;
System.out.println("
"+ subtraction2);
break;
case 4:
float multiplication = no1*no2;
System.out.println("
"+ multiplication);
break;
case 5:
double division1 = no1/no2;
System.out.println("
"+ division1);
break;
case 6:
double division2 = no2/no1;
System.out.println("
"+ division2);
break;
case 7:
System.out.println("
"+ "Please enter the power."+"
");
int exponent = num.nextInt();
double exponent1 = (int) Math.pow(no1, exponent);
System.out.println("
"+ exponent1);
break;
case 8:
System.out.println("
"+ "Please enter the power."+"
");
int exponenttwo = num.nextInt();
double exponent2 = (int) Math.pow(no2, exponenttwo);
System.out.println("
"+ exponent2);
break;
default:
System.out.println("
"+ "There isnt any such option matching your entry!"+"
");
break;
}
System.out.println("
"+ "Would you like to perform more calculations? Respond with yes or no."+"
");
retry = num.next();
again = "yes";
}while(retry.equalsIgnoreCase(again));
另一答案
我只是为了扩展nusaK的答案。
- 您应该声明诸如Scanner之类的实用程序，这些实用程序可以在for循环之外多次使用。
[将Scanner num = new Scanner(System.in);放入循环中时，每次循环运行都会创建一个新的扫描仪对象。由于我们始终从System.in进行扫描，因此我们可以使用同一对象扫描所有迭代。
由于Java自己管理内存，所以这不是什么大问题，但是可能是其他语言。
Scanner num = new Scanner(System.in);
String again = "yes"; // you can initialize again here
String retry=""; // always initialize in languages like Java to avoid errors.
do {
...
}
while((retry=num.next()).equalsIgnoreCase(again));
// u can also use this, i.e. assign and evaluate at the same time but it's harder to read.
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