java - 如何让java接受一行输入，显示结果，并要求更多输入？

Question

我正在创建一个Caesar Cypher程序，我需要让用户可以输入一行，单击回车，计算机将显示结果(同一行，但每个字母移动一定量)，然后程序应该能够在下一行接收更多输入，显示结果等。直到连续单击回车键两次。

所需输出的示例:

How many characters do you want to cycle backwards by?: (user inputs integer) 5
Enter a sentence: I hear Canada is a great place to visit.
D czvm Xvivyv dn v bmzvo kgvxz oj qdndo.
Good thing that our school is one of the best schools around!
Bjjy ocdib ocvo jpm nxcjjg dn jiz ja ocz wzno nxcjjgn vmjpiy!

当在空行上单击回车键时，上述程序结束。我是个新手，感谢您的帮助!

代码:https://pastebin.com/eyJyd81W

 System.out.print("How many characters do you want to cycle backwards by?: ");
    int cycles = sc.nextInt();

    System.out.print("Enter a sentence: ");
    String r = sc.nextLine();
    String sentence = sc.nextLine();

    while (sentence != null) {//Beginning of a while loop. 

        if (sentence.isEmpty()) { //If the enter key is clicked when the line is empty, the loop breaks.
            System.out.println(" ");
            break;

        }
        if (sc.hasNextLine()) { //If the enter key is clicked when there is input in the same line, the computer will go to the next line and scan for more input.

            for (int i = 0; i < sentence.length(); i++) {

                int letter = 0;
                char l = ' ';
                int difference = 0;
                int let = 0;

                letter = ((int) sentence.charAt(i));
                let = letter;

                if (let < 91 && let > 64) { //Check if uppercase

                    if (let - cycles < 65) { //if letters are still valid after subtracting cycles
                        difference = -(let - 65 - cycles);
                        let = 91 - difference;
                        l = (char) let;
                        System.out.print(l);

                    } else if ((let - cycles) >= 65) { //For basic backwards cycles (M (shifted back 3) becomes J)

                        let = letter - cycles;
                        l = (char) let;
                        System.out.print(l);
                    }
                } else if (let == 32) { //If a space is entered, this will add it.
                    System.out.print(" ");
                } else if (let > 96 && let < 123) { //If letters are lowercase

                    if (let - cycles < 97) {
                        difference = -(let - cycles - 97);
                        let = 123 - difference;
                        l = (char) let;
                        System.out.print(l);
                    } else if (let - cycles >= 96) {
                        let = letter - cycles;
                        l = (char) let;
                        System.out.print(l);
                    }
                } else { //if special characters are typed
                    l = (char) let;
                    System.out.print(l);
                }

            }
            sentence = sc.nextLine();
        } else {
            sentence = null;
        }

    }
}
}

我尝试创建一个 while 循环来扫描输入，但唯一的问题是它要求两个输入，显示 2 个结果，并要求在与前 2 个结果相同的行上提供更多输入。如果这有任何意义的话。

Answer 1

你们已经很接近了。这有点简单。

public static void main(String[] args) {

    Scanner sc = new Scanner(System.in);

    System.out.print("How many characters do you want to cycle backwards by?: ");
    int cycles = sc.nextInt();

    System.out.print("Enter a sentence: ");
    sc.nextLine();

    while (sc.hasNextLine()) {//Beginning of a while loop.

        String sentence = sc.nextLine();

        if (sentence.length() == 0)
            break;

        for (int i = 0; i < sentence.length(); i++) {

            int letter = 0;
            char l = ' ';
            int difference = 0;
            int let = 0;

            letter = ((int) sentence.charAt(i));
            let = letter;

            if (let < 91 && let > 64) { //Check if uppercase

                if (let - cycles < 65) { //if letters are still valid after subtracting cycles
                    difference = -(let - 65 - cycles);
                    let = 91 - difference;
                    l = (char) let;
                    System.out.print(l);

                } else if ((let - cycles) >= 65) { //For basic backwards cycles (M (shifted back 3) becomes J)

                    let = letter - cycles;
                    l = (char) let;
                    System.out.print(l);
                }
            } else if (let == 32) { //If a space is entered, this will add it.
                System.out.print(" ");
            } else if (let > 96 && let < 123) { //If letters are lowercase

                if (let - cycles < 97) {
                    difference = -(let - cycles - 97);
                    let = 123 - difference;
                    l = (char) let;
                    System.out.print(l);
                } else if (let - cycles >= 96) {
                    let = letter - cycles;
                    l = (char) let;
                    System.out.print(l);
                }
            } else { //if special characters are typed
                l = (char) let;
                System.out.print(l);
            }

        }
        System.out.println();
    }
  }
}