Question

我刚刚开始使用C ++ Primer Plus，我遇到了一些小问题。

const int MONTHS = 12;
const int YEARS = 3;
int sales[YEARS][MONTHS] = {0};
const string months[MONTHS] = {"January", "February", "March", "April", "May", "June", "July",
                               "August", "September", "October", "November", "December"
                              };

for (int year = 0; year < YEARS; year++)
{
    for (int month = 0; month < MONTHS; month++)
    {
        cout << "Please enter year " << year + 1 << " book sales for the month of " << months[month] << ": \t";
        cin >> sales[year][month];

    }
}

int yearlyTotal[YEARS][3] = {0};
int absoluteTotal = 0;

cout << "Yearly sales:" << endl;

for (int year = 0; year < YEARS; year++)
{
    cout << "Year " << year + 1 << ":";

    for (int month = 0; month < MONTHS; month++)
    {
        absoluteTotal = (yearlyTotal[year][year] += sales[year][month]);

    }

    cout << yearlyTotal[year][year] << endl;

}

cout << "The total number of books sold over a period of " << YEARS << " years is: " << absoluteTotal << endl;

我希望显示这三年的总数。其余的代码工作正常：输入很好，个人年度输出很好，但我不能将三年加在一起，最终总数。

每个选项的示例数据都会输入1，为我提供三个12总计：

第1年：12年第2年：12 第3：12年

3年期间销售的书籍总数为：12

最终的12显然应该是36。

我确实在一个点上完成了工作，但我没有完成个人工作。我搞砸了它并扭转了局面。

Answer 1

看起来你每次迭代都会重置absoluteTotal。你真的想要吗？

也许这就是你想要的？：

absoluteTotal += (yearlyTotal[year][year] += sales[year][month]);

Answer 2

#include <iostream>
#include <string>
using namespace std;
int main (void)
{
const int MONTHS = 12;
const int YEARS = 3;
int sales[YEARS][MONTHS] = {0};
const string months[MONTHS] = {"January", "February", "March", "April", "May", "June", "July",
                               "August", "September", "October", "November", "December"
                              };

for (int year = 0; year < YEARS; year++)
{
    for (int month = 0; month < MONTHS; month++)
    {
        cout << "Please enter year " << year + 1 << " book sales for the month of " << months[month] << ": \t";
        cin >> sales[year][month];

    }
}

int yearlyTotal[YEARS] = {0};
int absoluteTotal = 0;

cout << "Yearly sales:" << endl;

for (int year = 0; year < YEARS; year++)
{
    cout << "Year " << year + 1 << ":";

    for (int month = 0; month < MONTHS; month++)
    {
        yearlyTotal[year] += sales[year][month];
    }
    absoluteTotal += yearlyTotal[year];

    cout << yearlyTotal[year] << endl;

}

cout << "The total number of books sold over a period of " << YEARS << " years is: " << absoluteTotal << endl;
return 0;
}

您只需要在每月计数之外增加absoluteTotal
您只需要一维数组来计算年度数。

当涉及到这样的事情时，首先将它们写在纸上是有帮助的。

Answer 3

问题在于，你有absoluteTotal增量，你多次计算前几个月（因为yearlyTotal是一个计数器，它每个月递增一次，所以将它添加到absoluteTotal每次计算1个月12次，2个月11次等等。

相反，您希望该循环看起来像这样：

for (int year = 0; year < YEARS; year++)
{
    cout << "Year " << year + 1 << ":";

    for (int month = 0; month < MONTHS; month++)
    {
        (yearlyTotal[year][year] += sales[year][month]);

    }

    absoluteTotal += yearlyTotal[year][year]; 
    cout << yearlyTotal[year][year] << endl;

}

所以你每个月只计算一次。

编辑：Good Person关于只需要一维数组的评论当然也是正确的。：）

Answer 4

检查以下代码。它会起作用。

int yearlyTotal[YEARS];
int absoluteTotal = 0;

cout << "Yearly sales:" << endl;

for (int year = 0; year < YEARS; year++)
{
    yearlyTotal[year] = 0;

    cout << "Year " << year + 1 << ":";

    for (int month = 0; month < MONTHS; month++)
    {
        yearlyTotal[year] += sales[year][month];
        absoluteTotal += sales[year][month];
    }

    cout << yearlyTotal[year] << endl;

}

cout << "The total number of books sold over a period of " << YEARS << " years is: " << absoluteTotal << endl;

C ++ Primer Plus：2D阵列

4 个答案: