Question

我要做的是将数据输入到数组中，该数组最多可容纳200个变量，或者直到它到达文件末尾。如果文件超过200个变量，这会不会继续添加？这是我到目前为止所写的：

另外，如果没有在没有分配任何内容的元素中打印0，你会以相反的顺序输出它吗？

#include<iostream>
#include<fstream>
#include<iomanip>

using namespace std;

const int SIZE = 200;
int tripNumber[SIZE];
double finalTrip[SIZE];
double fuel, waste, misc, discount, final;
double totalFuel, totalWaste, totalMisc, totalDiscount, totalFinal;


int main()
{
cout << "Welcome to NAME's Space Travel Company" << endl;
cout << "Trip No" << "\t" << "Fuel" << "\t" << "Waste" << "\t" << "Misc" << "\t"   << "Discount Fuel" << "\t" << "Final Cost" << endl;

ifstream inp_1("TripInput.txt");

    for(int i = 0; i = !inp_1.eof(); i++)
    {
        inp_1 >> tripNumber[i] >> fuel >> waste >> misc;
        discount = fuel - (fuel * .10);
        final = discount + waste + misc;

        totalFuel += fuel;
        totalWaste += waste;
        totalMisc += misc;
        totalDiscount += discount;
        totalFinal += final;

        cout << setprecision(0) << tripNumber[i];
        cout << setprecision(2) << fixed << "\t " << fuel << "\t " << waste << "\t " << misc << "\t " << discount << "\t\t" << final << endl;

        finalTrip[i] = final;
    }


cout << "Totals" << "\t" << totalFuel << "\t" << totalWaste << "\t " << totalMisc << "\t " << totalDiscount << "\t\t" << totalFinal << endl;

inp_1.close();

system("PAUSE");
return 0;

}

Answer 1

尝试像这样控制你的循环：

for(int i = 0; i < SIZE; i++)
{
    inp_1 >> tripNumber[i] >> fuel >> waste >> misc;
    if (!inp_1)
        break;
    // etc...
}

您应该在输入命令之后立即检查文件状态，如上所述。 for循环确保数组不会溢出。

Answer 2

尝试

for(int i = 0; i < 200 && !inp_1.eof(); i++)
{
    // .....
}

Answer 3

您不检查文件中的记录数是否大于SIZE。

还不清楚为什么将变量定义为全局变量。至少燃料，废物和混合物可能是环路的局部变量。

在我看来，编写

会更正确

std::ifstream inp_1( "TripInput.txt" );

int i = 0;
std::string record;
while ( i < SIZE && std::getline( inp_1, record ) )
{
    if ( record.find_first_not_of( " " ) == std::string::npos ) continue;

    int fuel = 0, waste = 0, misc = 0;

    std::istringstream is( record );
    is >> tripNumber[i] >> fuel >> waste >> misc;

    discount = fuel - (fuel * .10);
    final = discount + waste + misc;

    totalFuel += fuel;
    totalWaste += waste;
    totalMisc += misc;
    totalDiscount += discount;
    totalFinal += final;

    std::cout << std::setprecision( 0 ) << tripNumber[i];
    std::cout << std::setprecision( 2 ) << std::fixed << "\t " 
                                        << fuel << "\t " 
                                        << waste << "\t " 
                                        << misc << "\t " 
                                        << discount << "\t\t" 
                                        << final << std::endl;

    finalTrip[i] = final;

    ++i;
}

c ++一旦达到数组大小或eof就停止循环

3 个答案: