如果循环不起作用。跑步时显示重复的cout。

Question

我正在尝试制作一个随机数生成器猜测游戏，这将允许用户选择一个范围。挑选范围后，用户将尝试猜测数字，直到他们做对。我是c ++的新手，不明白为什么两个cout输出在屏幕上。我是c ++的新手，无法弄清楚原因。我正在使用visual studio 17。

#include "stdafx.h"
#include <iostream>
#include <time.h>
#include <cstdlib>
using namespace std;



int main()
{
    int userNum;
    char choice;
    int numattempts = 0;
    int randNumber;
    srand(time(0));




cout << "Welcome to the number guessing game\n" << "Please choose what range you want to guess from\n" << " '1' = 0-20\n '2'= 0-50\n '3'= 0-100\n ";
cin >> choice;



if (choice == '1')
{

    randNumber = 0 + rand() % 20;

    cout << "Enter a number between 0 and 20\n";
    cin >> userNum;
    cout << randNumber;


    do {

        if (userNum < randNumber)
        {
            cout << "Number is Higher\n";
            cin >> userNum;
        }

        else if (userNum > randNumber)
        {
            cout << "Number is Lower\n";
            cin >> userNum;
        }

        else (userNum == randNumber);
        {
            cout << "Congrats You got it!\n";

        }

    } while (userNum != randNumber);
}

Answer 1

如果在最后一次检查中你错过了另一个，不应该在那里加分号。 尝试调试，你会发现它应该像这样

do {

        if (userNum < randNumber)
        {
            cout << "Number is Higher\n";
            cin >> userNum;
        }
        else if (userNum > randNumber)
        {
            cout << "Number is Lower\n";
            cin >> userNum;
        }
        else if(userNum == randNumber)
        {
            cout << "Congrats You got it!\n";
        }

    } while (userNum != randNumber);