c++ - 生成随机数的乐透 gui 应用程序

Question

#ifndef LOTTO_H
#define LOTTO_H
#include <QWidget>
#include <QLabel>
#include <QTextEdit>
#include <QPushButton>
#include <QGridLayout>

class lotto : public QWidget
{
    Q_OBJECT

private:
    //widget data members
    QLabel* numbersLabel;
    QTextEdit* numEdit;
    QPushButton* lotusButton;

public slots:
     int generateLotteryNumbers ();
     void displayNumbers();

public:
    lotto();
};

#endif // LOTTO_H




     #include "lotto.h"
        #include <stdlib.h>
        #include <time.h>
        #include <QWidget>
        #include <QGridLayout>
        #include <iostream>
        #include <sstream>
        #include <QString>
        #include "lotto.h"
        using namespace std;

        lotto::lotto(){
            setWindowTitle("Lotto Numbers");
            QGridLayout* layout = new QGridLayout(this);
            lotusButton = new QPushButton ("Lotto Numbers");
            numbersLabel = new QLabel ("Your lucky numbers are:");
            numEdit = new QTextEdit();
            layout->addWidget(lotusButton, 0,0);
            layout->addWidget(numbersLabel, 1,0);
            layout->addWidget(numEdit, 1,1);
            setLayout(layout);
          //connect signals and slots
            connect(lotusButton,SIGNAL(clicked()),this, SLOT(generateLotteryNumbers()));
        }
        int lotto::generateLotteryNumbers (){
            srand ( time(NULL) );
               int i, j, num, duplicates, numbers[6];
                for ( i = 0; i < 6; i++ ) {
                   do {
                       num = 1 + rand()%49;
                       duplicates = 0;
                       for ( j = 0; j < i; j++ ) {
                           if ( numbers[ j ] == num ) duplicates = 1;
                       }
                   }
                   while (duplicates);
                   numbers[ i ] = num;
            }

        }

        void lotto::displayNumbers(){
            numEdit->setText(QString::number(generateLotteryNumbers()));
        }

我尝试在文本编辑框中显示 6 个乐透号码。使用lineedit更好吗？当我单击乐透号码按钮时，文本框仍然为空。为什么？如何让文本框（或行框）显示数字？

我试过这个：

void lotto::displayNumbers(){
    srand ( time(NULL) );
       int i, j, num, duplicates, numbers[6];
        for ( i = 0; i < 6; i++ ) {
           do {
               num = 1 + rand()%49;
               duplicates = 0;
               for ( j = 0; j < i; j++ ) {
                   if ( numbers[ j ] == num ) duplicates = 1;
               }
           }
           while (duplicates);
           numbers[ i ] = num;
    }
    numEdit->setText(QString::number(num));
}

每次单击按钮时，我都会得到一个不同的数字（一次一个）

Answer 1

正如我从您的代码中看到的lotto::displayNumbers那样，单击按钮后甚至没有调用该方法。按钮点击信号lotto::generateLotteryNumbers改为连接到方法。

我也看不到该lotto::generateLotteryNumbers方法中的任何返回语句。

顺便说一句，如果您在调试器中花费一分钟，您可以自己弄清楚。