CODEWITHSUNDEEP
c++pointers
user2990286
user2990286

Reputation: 139

convert char* to char? c++

I figured this question had been asked a million times but I can't find the answer anywhere. Should be simple. Ok so I have a struct in my .h file:

struct question{
    string programNum;
    string programDesc;
    string programPoints;
    string programInput;
    char programQuestion;
};

And then I have function initiated in the .h and arguments in .cpp:

void setQuestionFileName(question q, char fileName){
    q.programQuestion = fileName;

}

Ok all is well so far. Now in main I have the issue of trying to store argv[1] in programQuestion:

char* fileName = argv[count+1];

followed by:

setQuestionFileName(questions[count],fileName);
cout << questions[count].programQuestion << endl;

I'm not real good with pointers so if anyone could help me store the char* argv into the char questions[count].programQuestion that would be amazing. Thank you!

Upvotes: 3

Views: 4309

Answers (2)

user2990286
user2990286

Reputation: 139

I'm going to post the code, I think it may work better that way. This is the .h:

      using namespace std;
      // Data

      struct question{
      string programNum;
      string programDesc;
      string programPoints;
      string programInput;
      char* programQuestion;
      };

      void setQuestionFileName(question* q, char* fileName);
      void display(question* q);
      void display(question* q);

This is the .cpp

    using namespace std;


    void setQuestionFileName(question* q, char* fileName){
        strcpy(q->programQuestion, fileName);
    }

    void display(question* q){

           cout << "Description           =  "   << q->programDesc     << endl;
           cout << "Number of Points      =  "   << q->programPoints   << endl;
           cout << "Name of Question File =  "   << q->programQuestion << endl;

    }

    // Not used or tested yet
    int myCompare (const void * a, const void * b ) {
               const char *pa = *(const char**)a;
               const char *pb = *(const char**)b;

               return strcmp(pa,pb);
     }

And main.cpp:

     using namespace std;

     int main(int argc, char* argv[]){                                                              //or char** argv
     question* questions[argc-1];                                                           //Array of questions to be filled by loop.
     int sizeOfQuestions = argc;                                                                    //number of questions passed in at run time
     int numLines = 0;                                                                          //number of lines in file
     for(int i=0;i<argc;i++){                                                                   //Test loop to make sure the command line file names are read in
              std::cout << argv[i] << " says hello" << std::endl;
     }
     for(int count=0;count<sizeOfQuestions-1;count++){                                          //This loop places the information from the files into structs
     //char fileName = argv[count+1];
     char* fileName = argv[count+1];
     cout << "Problem number:  " << count+1 << "\t Working with file " << fileName << endl;
     std::fstream questionFile (fileName, std::fstream::in);                                    //Open the file
     if(questionFile.good()){
        cout << "File Opened" << endl;
        setQuestionFileName(questions[count],fileName);
        cout << questions[count]->programQuestion << endl;
        getline(questionFile,questions[count]->programNum);
        getline(questionFile,questions[count]->programDesc);
        getline(questionFile,questions[count]->programPoints);
        getline(questionFile,questions[count]->programInput);
        display(questions[count]);
        questionFile.close();
     }else{
        cout << "Could not open file!!!" << endl;
     }

 }

 return 0;

}

The way it is now, I'm getting a segmentation fault.

Upvotes: 1

Daniel
Daniel

Reputation: 2185

Change your programQuestion from char to char*

And, this function

void setQuestionFileName(question q, char fileName){
    q.programQuestion = fileName;

}

I think it should be

void setQuestionFileName(question& q, char* fileName){
    strcpy(q.programQuestion, fileName);
}

Hardly there is a file with only 1-character name.

Upvotes: 0

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