Loops 循环概念程序_Loops_For Loop_Foreach_While Loop

Loops 循环概念程序

loops for-loop

Loops 循环概念程序,loops,for-loop,foreach,while-loop,Loops,For Loop,Foreach,While Loop,我一直在尝试学习Java，并在短时间内尝试了一些不同的概念。我决定做一个循环程序，以进一步巩固我对不同类型循环的了解下面的程序旨在接受用户输入，在我创建的每个循环类中创建一个不同的变量，并循环将整数增加1的次数。 e、 g 输入二, foreach 1 foreach 2 而1 而2 一两个然而，我得到的输出是完全不同的程序制作后。对于用户输入的每一个高/低数字，以及每重复0 49次，我得到最多49+-1的For循环。While循环不运行。在谷歌搜索和查看StackOverflow之后，

我一直在尝试学习Java，并在短时间内尝试了一些不同的概念。我决定做一个循环程序，以进一步巩固我对不同类型循环的了解

下面的程序旨在接受用户输入，在我创建的每个循环类中创建一个不同的变量，并循环将整数增加1的次数。 e、 g

输入二,

foreach 1 foreach 2 而1 而2 一两个

然而，我得到的输出是完全不同的程序制作后。对于用户输入的每一个高/低数字，以及每重复0 49次，我得到最多49+-1的For循环。While循环不运行。在谷歌搜索和查看StackOverflow之后，我一辈子都搞不清楚为什么我的程序不起作用

}

每次运行后都没有重置loopNumber，这会导致while循环立即退出。我会避免在您声明的几乎每个变量中使用static。虽然我猜在这种情况下是必需的。您正在将I和循环初始化为与WhileLoop中LoopPlay.loopNumber的当前值相同的值。因此，条件i

import java.io.IOException;

public class LoopPlay {
    static int loopNumber = 0;
    public static void main (String [] args){
        System.out.println ("Please enter a number to loop by");
        try {
            loopNumber = System.in.read();
            ForLoop.DoLoop();
            WhileLoop.DoLoop();
            EnhancedForLoop.DoLoop();
        } catch (IOException e) {
            System.out.println("Did you enter an integer?");
            main(args);
            e.printStackTrace();
        }       
    }
}



public class ForLoop extends LoopPlay{
    static int loops = LoopPlay.loopNumber;
    public static void DoLoop (){
        int i;
        for (i=0; i<loops; i++){
            System.out.println ("Forloop = " + i);
        }
    }
}



public class WhileLoop extends LoopPlay {
    static int loops = LoopPlay.loopNumber;
    public static void DoLoop(){
        int i = LoopPlay.loopNumber;
        while (i < loops){
            System.out.println("Whileloop =" + loops);
            loops++;
        }
    }
}



public class EnhancedForLoop extends LoopPlay {

    static int [] loop = new int [LoopPlay.loopNumber];
    static int loops = LoopPlay.loopNumber;

    public static void ForLoop (String [] args){
        int i;
        for (i=0; i<loops; i++){
            loop[i] = i;
        }
    }
    public static void DoLoop () {
        for (int x : loop){
            System.out.println("EnhancedForLoop = " + x);
        }
    }
}

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import java.util.Scanner; // Import scanner class for reading user input

public class LoopPlay { // Sets the loopNumber and allows user to select loop type

    static int loopNumber = 0; // Instantiates loopNumber for calculating num of times to loop
static Scanner scan = new Scanner(System.in); // Creates a scanner object called scan

public static void main (String [] args){ // Primary method 
    System.out.println ("Please enter a number to loop by"); // Asks user for input

    loopNumber = scan.nextInt(); // Sets loopNumber to user input

    System.out.println("\n\n\n\n\n\n\n\n\n\n\n"); // Clears the console
    System.out.println("What would you like to do?"); // Menu for user selections 
    System.out.println("1. For Loop");
    System.out.println("2. While Loop");
    System.out.println("3. Enhanced For Loop");
    System.out.println("4. Do all");

    int choice = scan.nextInt(); // Sets user choice to choice variable
    System.out.println("\n\n\n\n\n\n\n");

    switch (choice){ // Creates a switch statement to call loops based on choice
    case 1: choice = 1;
    ForLoop.DoLoop();
    break;

    case 2: choice = 2;
    WhileLoop.DoLoop();
    break;

    case 3: choice = 3;
    EnhancedForLoop.DoLoop();
    break;

    case 4: choice = 4;
    ForLoop.DoLoop();
    WhileLoop.DoLoop();
    EnhancedForLoop.DoLoop();
    }
}
}





public class WhileLoop extends LoopPlay { // This class runs a while loop using       loopNumber
public static void DoLoop(){
    int i = loopNumber; // Sets i to loop variable for this method
    while (i > 0 ){ // Outputs the value of i for loopNumber amount of times
        System.out.println("Whileloop = " + i);
        i--;
    }
    LoopPlay.main(null); // Calls the main method to restart process
}

public class ForLoop extends LoopPlay{ // Class for While Loop
public static void DoLoop (){
    int i; // Creates a looping variable local to DoLoop method
    for (i=loopNumber; i > 0; i--){ // Sets i to loop variable and loops that many times
        System.out.println ("Forloop = " + i); // Shows where the loop is up to
    }
    LoopPlay.main(null); // Restarts the program
}

import java.lang.reflect.Array;


public class EnhancedForLoop extends LoopPlay { // Class to run through using an enhanced for loop

static int enhancedLoop = (loopNumber); // creates an array with loopNumber amount of slots

public static void ForLoop (String [] args){ // Populates the enhancedLoop array
    int i;                                   // with values of i
    for (i=loopNumber; i > 0; i--){
        enhancedLoop(i) = i;
    }
}
public static void DoLoop () { // Runs the enhanced loop to display all values of enhancedLoop
    for (int x: enhancedLoop){
        System.out.println("EnhancedForLoop = " + x);
    }
    LoopPlay.main(null); // Restarts the program
}