试图检索包含空格的字符串的最后一个字母

Question

是的，所以我在尝试使用 .substring 检索最后一个字母时遇到了一点困难。例如，如果我输入“100C”，它将正常工作并且变量 celOrFar 将 = "C"。然而，用户应该在数字后插入一个 space，但这样做会给我一个不正确的结果。 “100 C”会给我“0”而不是 C，而“1234 5678C”会给我 4！我仍然是 Java 的初学者，所以非常感谢您的帮助！

public static void stateOfWater() {     

    System.out.println("Enter a temperature followed by a space and C / F: ");
    String userInput = input.next();
    String celOrFar = userInput.substring(userInput.length()-1);

    String degreeString = userInput.trim();
    degreeString = degreeString.replace("C", "");
    degreeString = degreeString.replace("F", "");
    degreeString = degreeString.replace("f", "");
    degreeString = degreeString.replace("c", "");

    int degree = Integer.parseInt(degreeString);    

    if (celOrFar.equals("C")|| celOrFar.equals("c")) {          
        if (degree <= 0) {System.out.println("Your water is a solid at " +userInput);}          
        if (degree >= 100) {System.out.println("Your water is a gas at " +userInput);}      
        if (degree >0 && degree <100) {System.out.println("Your water is a liquid at " +userInput);}            
    }

    if (celOrFar.equals("F") || celOrFar.equals("f")) {         
        if (degree <= 32) {System.out.println("Your water is a solid at " +userInput);}         
        if (degree >= 212) {System.out.println("Your water is a gas at " +userInput);}          
        if (degree >32 && degree <212) {System.out.println("Your water is a liquid at " +userInput);}           
    }   
}

Answer 1

scanner.next 读取字符，直到遇到 space。如果你想阅读包含 space 的完整行，那么你需要使用 nextLine。见下文。

public static void stateOfWater() {     

System.out.println("Enter a temperature followed by a space and C / F: ");
String userInput = input.nextLine(); // this will read the complete line including spaces.
String celOrFar = userInput.substring(userInput.length()-1);

String degreeString = userInput.trim();
degreeString = degreeString.replace("C", "");
degreeString = degreeString.replace("F", "");
degreeString = degreeString.replace("f", "");
degreeString = degreeString.replace("c", "");

int degree = Integer.parseInt(degreeString);    

if (celOrFar.equals("C")|| celOrFar.equals("c")) {          
    if (degree <= 0) {System.out.println("Your water is a solid at " +userInput);}          
    if (degree >= 100) {System.out.println("Your water is a gas at " +userInput);}      
    if (degree >0 && degree <100) {System.out.println("Your water is a liquid at " +userInput);}            
}

if (celOrFar.equals("F") || celOrFar.equals("f")) {         
    if (degree <= 32) {System.out.println("Your water is a solid at " +userInput);}         
    if (degree >= 212) {System.out.println("Your water is a gas at " +userInput);}          
    if (degree >32 && degree <212) {System.out.println("Your water is a liquid at " +userInput);}           
   }   
}

试图检索包含空格的字符串的最后一个字母

Trying to retrieve the last letter of a String which includes spaces

java

string

whitespace

substring