我在阅读输入文件时遇到问题。程序完美地读取输入文件并且工作得很好，除了它读取文档中的最后一个人名两次。
这是程序输出的一部分，显示了hooper，grace name两次。谢谢你的期待
****Input file lab10data1.txt is open for reading.
Number of student records read = 17
The following student(s) have the highest score
Einstein, Albert
List of All the Students in the class
Student Name Test Score Grade
------------------------------------------
Fibonacci, Leonardo 63 D
Huffman, David 79 C
Augusta, Ada 91 A
Goldbach, Christian 81 B
Venn, John 100 A
Church, Alonzo 72 C
Einstein, Albert 105 F
Fermat, Pierre 84 B
Kruskal, Joseph 66 D
Cantor, Georg 67 D
Turing, Alan 85 B
Chebysheva, PL 100 A
DeMorgan, Augustus 79 C
Karnaugh, Maurice 72 C
Babbage, Charles 98 A
Hooper, Grace 95 A
Hooper, Grace 95 A // RIGHT HERE it reads grace twice
这是代码
#include<iostream>
#include<fstream>
#include<string>
#include<iomanip>**
using namespace std;
struct StudentType
{
string studentName;
int testScore;//Between 0 and 100
char grade;
};
void PrintNameHeader(ostream& out);
bool OpenInputFile(ifstream& inFile, string& infilename ); //OPEN input file
void Pause();// Pause
void ReadStudentData(ifstream& infile, StudentType student[], int& );// Read student infp including first and last name and test score
void AssignGrades(StudentType student[], int);//assign grades to each student
int HighestScore(const StudentType student[], int );//Get the highest scores
void PrintNamesWithHighestScore(const StudentType student[], int);//Print name/s with highest Scores
void DisplayAllStudents(const StudentType student[], int);//Display all students
void GetLowHighRangeValues(const StudentType student[], int, int& , int&);//for example a student types 50 100 , it will get all students within that range
void DisplayStudentsInRange(const StudentType student[], int, int, int);// display students in that range
void SortStudentsByName(StudentType student[], int);// sort students by name
void SortStudentsByScore(StudentType student[], int);// sort students by test score highest to lowest
void FormatNameScoreGrade(ostream& out);
const int NUM_STUDENTS = 20;
int main()
{
ifstream infile;
string inFilename;
StudentType student[NUM_STUDENTS];
int numStudents = 0;
PrintNameHeader(cout);
if(!OpenInputFile(infile,inFilename)) return 1;
ReadStudentData(infile, student, numStudents);
infile.close();
AssignGrades(student, numStudents);
PrintNamesWithHighestScore(student, numStudents);
cout <<"List of All the Students in the class" << endl;
DisplayAllStudents(student, numStudents);
Pause();//Pause
int lownum, highnum;
char answer;
do {
GetLowHighRangeValues(student, numStudents, lownum, highnum);
DisplayStudentsInRange(student, numStudents, 70, 90);
cout <<"Do you want to see another range of scores [y/n]?";
cin >> answer;
} while( answer == 'y' || answer == 'Y');
SortStudentsByName(student, numStudents);
Pause();//Pause
SortStudentsByScore(student, numStudents);
return 0;
}
//Function definitions
void PrintNameHeader(ostream& out)
{
//Display name header on screen
}
void FormatNameScoreGrade(ostream& out)
{
out << setw(10) << " Student Name" << setw(20) <<"Test Score" << setw(10) <<"Grade" << endl;
out <<" ------------------------------------------" << endl;
}
bool OpenInputFile(ifstream& inFile, string& infilename)
{
cout << "Enter the name of the .txt file that you want to open for input.\n";
cout << "Do not put spaces in the file name : ";
cin >> infilename;
cout << endl;
inFile.open(infilename.c_str());
if (inFile.fail())
{
cout << "Sorry, the input file " << infilename <<" was not found"<< endl;\
return false;
}
cout << "Input file " << infilename << " is open for reading.\n\n";
return true;
}
void Pause()
{
cout << endl;
cin.ignore(80, '\n');
cout<<"Please hit the enter key to continue...\n";
cin.get();
}
void ReadStudentData(ifstream& infile, StudentType student[], int& numStudents)
{
string firstName, lastName;
int testScore;
int count = 0;
while(infile)
{
infile >> firstName >> lastName >> testScore;
student[count].studentName = lastName + ", " + firstName;
student[count].testScore = testScore;
count++;
}
numStudents = count;
cout << "Number of student records read = " << numStudents << endl;
}
void AssignGrades(StudentType student[], int numStudents)
{
int testscore;
char grade;
for(int i = 0; i < numStudents; i++)
{
testscore = student[i].testScore;
if(testscore >= 90 && testscore <=100)
grade = 'A';
else if(testscore >= 80 && testscore <90)
grade = 'B';
else if(testscore >= 70 && testscore <80)
grade = 'C';
else if(testscore >= 60 && testscore <70)
grade = 'D';
else
grade = 'F';
student[i].grade = grade;
}
}
int HighestScore(const StudentType student[], int numStudents)
{
int highest = student[0].testScore;
for(int i = 1; i < numStudents; i++)
{
if(highest < student[i].testScore) highest = student[i].testScore;
}
return highest;
}
void PrintNamesWithHighestScore(const StudentType student[], int numStudents)
{
int highest = HighestScore(student, numStudents);
cout << endl << "The following student(s) have the highest score" << endl << endl;
for(int i = 0; i < numStudents; i++)
{
if (student[i].testScore == highest)
{
cout << " " << student[i].studentName;
}
}
cout << endl;
}
void DisplayAllStudents(const StudentType student[], int numStudents)
{
cout << endl;
FormatNameScoreGrade(cout);
for(int i = 0; i < numStudents; i++)
{
cout << setw(20) << student[i].studentName << setw(10) << student[i].testScore << setw(10) << student[i].grade << endl;
}
cout << endl;
}
void GetLowHighRangeValues(const StudentType student[], int numStudents, int& lowRange, int& highRange)
{
int lowest = student[0].testScore;
for(int i = 1; i < numStudents; i++)
{
if(lowest > student[i].testScore) lowest = student[i].testScore;
}
lowRange = lowest;
highRange = HighestScore(student, numStudents);
}
void DisplayStudentsInRange(const StudentType student[], int numStudents, int lownum, int highnum)
{
cout <<"Enter two vales for the range of scores you want to look at: ";
cin >> lownum >> highnum;
cout << endl << "List of students with scores in the range " << lownum << " to " << highnum << endl << endl;
FormatNameScoreGrade(cout);
for(int i = 0; i < numStudents; i++)
{
if(student[i].testScore >= lownum && student[i].testScore <= highnum)
{
cout << setw(20) << student[i].studentName << setw(10) << student[i].testScore << setw(10) << student[i].grade << endl;
}
}
cout << endl;
}
void SortStudentsByName(StudentType student[], int numStudents)
{
StudentType temp;
for(int i = 0;i < numStudents - 1;i++)
{
for(int j = i + 1; j < numStudents;j++)
{
if(student[i].studentName > student[j].studentName)
{
temp = student[i];
student[i] = student[j];
student[j] = temp;
}
}
}
cout << endl;
cout << "List of Students sorted by Name" << endl;
DisplayAllStudents(student, numStudents);
}
void SortStudentsByScore(StudentType student[], int numStudents)
{
StudentType temp;
for(int i = 0;i < numStudents - 1;i++)
{
for(int j = i + 1; j < numStudents;j++)
{
if(student[i].testScore < student[j].testScore)
{
temp = student[i];
student[i] = student[j];
student[j] = temp;
}
}
}
cout <<"List of Students sorted by Score" << endl;
DisplayAllStudents(student, numStudents);
}
答案 0 :(得分：1)
变化：
while (infile)
{
infile >> firstName >> lastName >> testScore;
// ...
到
while (infile >> firstName >> lastName >> testScore)
{
// ...
以便在检查流之前执行读取。