Question

我在需要打印当天的部分遇到问题。我尝试制作第二个变量，但它不起作用。基本上我为他们的生日带了一个用户输入。然后我试着调用这个函数来确定出生日期（它确定代表一天的数字）。然后我试图将这个数字发送到接受数字的函数并用单词打印生日。我现在得到'int day2'重新定义的错误。

这是我的代码：

void determineDayOfBirth() {

    int day;
    int month;
    int year;
    char backslash;
    char backslash2;

    cout << "Enter your date of birth" << endl;
    cout << "format: month / day / year -->" << endl;
    cin >> month >> backslash >> day >> backslash2 >> year;

    if (isValidDate(month, day, year)) {
        int day2;
        cout << "You were born on a: ";
        int day2 = determineDay(month, day, year);
        printDayOfBirth(day2); 
        cout << endl;
        cout << "Have a great birthday!!!";
    }
    else {
        cout << "Invalid date";
    }
    return;
}

Answer 1

从第二个分配中删除int，您无法在同一个块中定义两次变量。

要修复您的代码，请替换：

    int day2;
    cout << "You were born on a: ";
    int day2 = determineDay(month, day, year);

使用：

    cout << "You were born on a: ";
    int day2 = determineDay(month, day, year);

Answer 2

你已经放了两次“int day2”，这确实是一个重新定义。你只需要定义一次“day2”：

if (isValidDate(month, day, year)) {
    int day2;
    cout << "You were born on a: ";
    day2 = determineDay(month, day, year); // REMOVE "int"
    printDayOfBirth(day2); 
    cout << endl;
    cout << "Have a great birthday!!!";
}
else {
    cout << "Invalid date";
}
return;

Answer 3

问题的原因是

    int day2;
    cout << "You were born on a: ";
    int day2 = determineDay(month, day, year);

第二个是重新定义day2。

从该行中删除int关键字，它将成为一个简单的作业。

Answer 4

您不能在同一范围内声明两个变量，因此day2在if块中声明两次。你可以直接写：

//if(){
     int day2 = determineDay(month, day, year);
//}

重新定义错误C ++

4 个答案: