Question

所以我现在是Java的初学者，我一直在玩字符串。现在，我想为用户提供输入选项"Enter a or b: "，并根据"a"或"b"提供输出

守则：

int a = 18;
int b = 22;

Scanner user_input = new Scanner (System.in);

String first_name;
System.out.println("Enter your first name: ");
first_name = user_input.next();

String last_name;
System.out.println("Enter your last name: ");
last_name = user_input.next();

String full_name;
full_name = first_name + " " + last_name;
System.out.println("You are: " + full_name);

String age;
System.out.println("Enter a or b: ");
age = user_input.next();

String age_a;
System.out.println("Your age is 18");
age = user_input(a);

我也在想也许可以使用一个函数，如：

if(user_input = a)
{
   System.out.println("Your age is 18.");
}

Answer 1

一旦你age，你必须检查价值，但因为它是String你必须使用String.equals()

if (age.equals("a"))
   System.out.println("Your age is 18");
else 
   System.out.println("Your age is 22");

如果您想检查答案是仅 a还是b，请使用while循环重复此问题，直到找到答案：

String age;
while (!age.equals("a") || !age.equals("b")) {
    // ask for age
}

Answer 2

您可以使用带有"string".equals("other_string")的if来比较它们：

int a = 18;
int b = 22;

Scanner user_input = new Scanner (System.in);

System.out.println("Enter your first name: ");
String first_name = user_input.next();

System.out.println("Enter your last name: ");
String last_name = user_input.next();

String full_name = first_name + " " + last_name;
System.out.println("You are: " + full_name);

System.out.println("Enter a or b: ");
String ageChoice = user_input.next();

String age = null;
if(ageChoice.equals("a")){
    age = String.valueOf(a);
}
else if(ageChoice.equals("b")){
    age = String.valueOf(b);
}
System.out.println("Your age is: " + age);

输入字符串选择

2 个答案: