无法识别Java中的变量
对于作业,我正在创建一个命令行程序,将输入的温度从摄氏度(C)更改为华氏度(F),反之亦然。程序运行正常,直到用户输入临时类型(C/F),然后它似乎无法识别用户输入。我做错了什么无法识别Java中的变量,java,if-statement,variables,user-input,command-line-arguments,Java,If Statement,Variables,User Input,Command Line Arguments,对于作业,我正在创建一个命令行程序,将输入的温度从摄氏度(C)更改为华氏度(F),反之亦然。程序运行正常,直到用户输入临时类型(C/F),然后它似乎无法识别用户输入。我做错了什么 public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.println("Please enter the temperature:");
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Please enter the temperature:"); //Prompts user for temperature
String temp = input.nextLine(); //Allows user to input temp data
double tempDouble = Double.parseDouble(temp); //Changes input from string to double
System.out.println("Is " + temp + " degrees in Celsius or Fahrenheit? (Enter C or F):"); //Prompts user for type of temp
String type = input.nextLine(); //Allows user to input temp type
if (type == "C") { //Checks if temp is Celsius
double tempF = 0;
tempF = (tempDouble * 1.8) + 32; //Converts temp to Fahrenheit
System.out.println(tempDouble + "C equals " + tempF + "F."); //Displays conversion of C to F
//Tf = Tc * 1.8 + 32
} else if (type == "F") { //Checks if temp is Fahrenheit
double tempC = 0;
tempC = (tempDouble - 32) / 1.8; //Converts temp to Celsius
System.out.println(tempDouble + "F equals " + tempC + "C.");
//Tc = (Tf - 32) / 1.8
}
System.out.println("Incorrect input for Celsius or Fahrenheit"); //Tells user they didn't input C or F correctly
}
代码中有两个问题
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Please enter the temperature:"); //Prompts user for temperature
String temp = input.nextLine(); //Allows user to input temp data
double tempDouble = Double.parseDouble(temp); //Changes input from string to double
System.out.println("Is " + temp + " degrees in Celsius or Fahrenheit? (Enter C or F):"); //Prompts user for type of temp
String type = input.nextLine(); //Allows user to input temp type
if ("C".equals(type)) { //Checks if temp is Celsius
double tempF = 0;
tempF = (tempDouble * 1.8) + 32; //Converts temp to Fahrenheit
System.out.println(tempDouble + "C equals " + tempF + "F."); //Displays conversion of C to F
//Tf = Tc * 1.8 + 32
} else if ("F".equals(type)) { //Checks if temp is Fahrenheit
double tempC = 0;
tempC = (tempDouble - 32) / 1.8; //Converts temp to Celsius
System.out.println(tempDouble + "F equals " + tempC + "C.");
//Tc = (Tf - 32) / 1.8
}else{
System.out.println("Incorrect input for Celsius or Fahrenheit"); //Tells user they didn't input C or F correctly
}
}
您正在执行``if(type==“C”)```,这将比较对象实例,执行“C”。等于(type)