解决方案

Question

我有一个代码项目，在该项目中我已经对其进行编译并运行，但似乎它只是返回一条错误消息，如

有人可以帮助我吗？

#include <iostream>
#include <iomanip>
#include <string>
#include <vector>
#include <fstream>
#include <stdlib.h>
#include <sstream>
using namespace std;

struct course
   {
   string CourseID;
   string CourseName;
   int CourseSemester;
   int CourseSKS;
   }c;
void printMenu_course();
void printReport_course(vector <course> x, int sem);
vector <course> readData_course(int sem);
void splitData(string temp1, string temp2[4]);
int ccounter;
int sem;
int main()
{  
      printMenu_course();
      return 0;
}

void printMenu_course()
{  
   char answer;
   cout << "PRINT MENU COURSE" << endl;
   cout << "Which semester of course that you want to print ?" <<endl;
      cin >> c.CourseSemester;
    cout << "Do you want to print [Y/N] ?";
      cin >>answer;
    if (answer== 'Y' || answer== 'y')
    {
       printReport_course(readData_course(sem), c.CourseSemester);
    }

    else if (answer == 'n' || answer == 'N')
    {
      cout << "Program Terminated.";
    }

    else
    cout << "Wrong Input.";

}
void splitData(string temp1, string temp2[4])
{
   int x=0;
   string mark = ",";
   size_t pos = 0;
   while ((pos = temp1.find(mark)) != string::npos ) 
   {
      temp2[x] = temp1.substr(0,pos);
      x++;
      temp1.erase(0, pos + mark.length());
   } temp2[x] = temp1;
}


vector <course> readData_course(int sem)
{  
   vector <course> x;
   ccounter = 0;
   string baris1, baris2[4];
   ifstream courFile;
   courFile.open("course.txt", ios::in);
   while(!courFile.eof())
   {
      courFile >> baris1;
      splitData(baris1,baris2);
      x.push_back(course());
      x[ccounter].CourseID = baris2[0];
      x[ccounter].CourseName = baris2[1];
      x[ccounter].CourseSemester = ::atof(baris2[2].c_str());
      x[ccounter].CourseSKS = ::atof(baris2[3].c_str());
      ccounter++;
   }courFile.close();
   return x; 
}

void printReport_course(vector<course> x, int sem)
{
   int num = 0;
   cout << "      COURSE DATA      \n";
   cout << "Semester " <<  sem << endl;
   cout << setw(5) << "No.";
   cout << setw(5) << "Course ID";
   cout << setw(25) << "Course Name";
   cout << setw(5) << "Course SKS \n";
   for(int i =0;i<ccounter;i++)
   {
      if(x[i].CourseSemester == sem)
      {
      cout << setw(5) << ++num;
      cout << setw(5) << x[i].CourseID;
      cout << setw(25) << x[i].CourseName;
      cout << setw(5) << x[i].CourseSKS << "\n"; 
      }

    }
}

当我将向量仅更改为temp2 [3]和baris2 [3]时，它可以运行而没有任何错误，但是如果它是temp2 [4]和baris2 [4]，则再次显示类似错误。

Answer 1

将程序减少到演示错误所需的最低限度，并添加几个调试语句

#include <iostream>
#include <string>
using namespace std;

void splitData(string temp1, string temp2[4])
{
    int x = 0;
    string mark = ",";
    size_t pos = 0;
    while ((pos = temp1.find(mark)) != string::npos)
    {
        temp2[x] = temp1.substr(0, pos);
        cout << temp2[x] << ": ";
        x++;
        temp1.erase(0, pos + mark.length());
        cout << x << ": " << temp1 <<"\n";
    }
    if (x >= 4)
    {
        cout << "Accessing temp2[x] with x = " << x << " when temp2 contains 4 elements\n";
    }
    temp2[x] = temp1;
}

int main()
{
    string temp2[4];
    splitData("A,B,C,D,", temp2);
}

我们得到以下输出：

A: 1: B,C,D,
B: 2: C,D,
C: 3: D,
D: 4: 
Accessing temp2[x] with x = 4 when temp2 contains 4 elements

清楚地表明x允许超出范围。为什么？计算

中的项目数

"A,B,C,D,"
 1 2 3 4 5

第五个元素为空。吕克·贝森（Luc Besson）不赞成。

解决方案

删除输入文件中的尾部逗号。

更好的解决方案

使用vector，以便元素的数量无关紧要。

#include <iostream>
#include <string>
#include <vector>
using namespace std;

vector<string> splitData(string temp1)
{
    vector<string> tokens;
    string mark = ",";
    size_t pos = 0;
    while ((pos = temp1.find(mark)) != string::npos)
    {
        tokens.push_back(temp1.substr(0, pos));
        temp1.erase(0, pos + mark.length());
    }
    tokens.push_back(temp1);
    return tokens;
}

int main()
{
    vector<string> tokens = splitData("A,B,C,D,");
    cout << "Number of tokens: " << tokens.size() << '\n';

    for (const string & token: tokens)
    {
        cout << token << '\n';
    }
    cout << "Done.\n";
}

输出：

Number of tokens: 5
A
B
C
D

Done.

不相关的评论

大多数变量的命名是错误的。 string temp1包含零信息。这使调试更加困难，因为您必须不断查看匿名变量的含义以及它们应该包含的内容。不要对自己这样做。使用描述性名称。另外，如果名称足够好，代码将自行注释。

C ++：进程死于信号6

1 个答案:

解决方案

更好的解决方案

不相关的评论