Question

新代码......

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

using namespace std;

void gradeg (double & average, string & grade)
{
    if (average >= 90)
        {
            grade = "A";
        }
        else if ((average < 90) & (average >= 80))
        {
            grade = "B";
        }
        else if ((average < 80) & (average >= 70))
        {
            grade = "C";
        }
        else if ((average < 70) & (average >= 60))
        {
            grade = "D";
        }
        else
        {
            grade = "F";
        }
}

void totalg (int & total, int & s1, int & s2, int & s3)
{
    total=(s1+s2+s3);
}

void averageg (double & average, int & total)
{
    average=total/3.0;
}

int main()
{
    ifstream fin;
    ofstream fout;

    fout.setf (ios::fixed);
    fout.setf (ios::showpoint);
    fout.precision (2);

    char filename[15];

    fin.open("input.txt");

    cout << "Please enter the name of your output file: ";
    cin >> filename;

    fout.open(filename);

    if (fin.fail())
    {
        cout << "Failed to open INPUT file." << endl;
        exit(1);
    }
    if (fout.fail())
    {
        cout << "Failed to open OUTPUT file." << endl;
        exit(1);
    }

    string grade, name;
    int s1, s2, s3, total=0;
    double average=0.0;


    fout << left << "Names" << setw(24) << "Score 1" << setw(10) << "Score 2" << setw(10) << "Score 3" << setw(10) << "Total" << setw(10) << "Average"<< setw(10) << "Grade \n";

    cout << "Reading from input files.....";

    while (! fin.eof())
    {
        fin >> name >> s1 >> s2 >> s3;

        totalg (total, s1, s2, s3);

        averageg (average, total);

        gradeg (average, grade);


        fout << left << name << setw(24) << s1 << setw(10) << s2 << setw(10) << s3 << setw(10) <<total << setw(10) << average << setw(10) << grade << "\n";

    }

    cout << "Your output file has been created and the computation results have been stored.";

    return 0;
}

新输出......

NamesScore 1                 Score 2   Score 3   Total     Average   Grade 
   DAN100                     70        85        255       85.00     B         
JANE78                      82        90        250       83.33     B         
PETER82                      84        91        257       85.67     B         
MINIE98                      100       75        273       91.00     A         
JOSEPH71                      62        100       233       77.67     C         
CHRISTOPHER91                      75        82        248       82.67     B         
BEN54                      84        77        215       71.67     C

Answer 1

使用“左”操纵器作为名称，然后使用数字的“右”操纵器：

fout << left << setw(19) << "Names" << right << setw(10) << "Score 1" << setw(10) << "Score 2" << setw(10) << "Score 3" << setw(10) << "Total" << setw(10) << "Average"<< setw(10) << "Grade" << '\n';

fout << left << setw(19) << name << right << setw(10) << s1 << setw(10) << s2 << setw(10) << s3 << setw(10) <<total << setw(10) << average << setw(10) << grade << "\n";

这是我得到的输出：

Names                 Score 1   Score 2   Score 3     Total   Average     Grade
DAN                       100        70        85       255     85.00         B
JANE                       78        82        90       250     83.33         B
PETER                      82        84        91       257     85.67         B
MINIE                      98       100        75       273     91.00         A
JOSEPH                     71        62       100       233     77.67         C
CHRISTOPHER                91        75        82       248     82.67         B
BEN                        54        84        77       215     71.67         C
BEN                        54        84        77       215     71.67         C

Answer 2

你犯的是一个非常简单的错误，即格式化操作符（例如setw）必须在之前它格式化的数据，如下所示：

fout << left << setw(24) << "Names" << setw(10) << "Score 1" << setw(10) << "Score 2" << setw(10) << "Score 3" << setw(10) << "Total" << setw(10) << "Average"<< setw(10) << "Grade \n"; fout << left << setw(24) << name << setw(10) << s1 << setw(10) << s2 << setw(10) << s3 << setw(10) <<total << setw(10) << average << setw(10) << grade << "\n"; // ^^^^^^^^^^^ NOTE THIS PART

单词Names将占用5个字符，后面会有19个空格。接下来，您将看到Score 1（7个字符），后跟3个空格，依此类推。

Names Score 1 Score 2 Ken Bloom 75 100 Alec 100 75

在C ++中输出到文件时如何排序

2 个答案: