Thread: issue with retrieving values and run time error

Hello, I have issues for the following piece of code :

Code:

#include <string>
#include <fstream>
#include <iostream>
#include <cstdlib>

#define print( text ) std::cout << text << "\n"

void extract_word( std::string & sentence , std::string & word )
{
    print( "extracting word" );
	// first, we need to get rid of space if it is there
	if( sentence[0] == ' ' )
	{
		sentence.erase(0, 1 );
	}

	std::size_t sizeofword = sentence.find_first_of(' ');
	word = sentence.substr(0, sizeofword);
	sentence.erase( 0 , sizeofword ); // remove each word from the sentence
	print(word);
}


void extract_grade( int * array , std::string & sentence )
{
    print( "extracting grade");
	std::size_t found;
	std::size_t bais = 0; // start position
	unsigned int count = 0;
	int value;
	// first, we need to get rid of space if it is there
	if( sentence[0] == ' ' )
	{
		sentence.erase(0, 1 );
	}

	found = sentence.find(' ', bais );
	 while(found != std::string::npos) // goes to the end of the string
	{

		value = std::atoi( sentence.substr( bais , found ).c_str() );
		print(value);
		array[ count++ ] = value;
		bais = found + 1;
		found = sentence.find(' ', bais );
	}

	while( count < 10 )
	{
		array[ count++ ] = -1;
	}
}



void init_program()
{
	std::ifstream file("gradebook.txt");
	std::string sentence;
	std::string fullname[5][2];
	int grades[5][10];
	unsigned int count = 0;
	if( !file.is_open())
    {
        std::cout << "Problem opening file.\n"<<std::endl;
		return;
    }
	while( std::getline(file, sentence) )
	{
	    sentence.push_back(' ');
	    print("extracting info");
	    print("getting firstname ");
		// get first name
		extract_word(sentence, fullname[ count++ ][ 0 ]);

		print("getting lastname ");
		// get second name
		extract_word(sentence, fullname[ count++ ][ 1 ]);
        print(sentence);
		print("getting grades ");
		// get grades
		extract_grade( &grades[ count++][0] , sentence );
		print("results");
        print( grades[count][0]  );
		print(" going to next person");
	}

	std::cout << "this is the check \n";
	// will check here
	std::cout<< " this is the first name "<< fullname[4][0] << " this is the last name " << fullname[4][1] << "\n";

    file.close();
}

int main(void)
{
    init_program();
    return 0;
}

I get errors retrieving the grade values extracted, and then I get a run time fault.

any suggestions?

Originally Posted by laserlight

I suggest defining a structure like this:

Code:

struct student
{
    std::string first_name;
    std::string last_name;
    std::vector<int> grades;
};

Overload operator>> to read into a student object. Reading into first_name and last_name would then be easy: just use the overloaded operator>> for std::string. Likewise, use the overloaded operator>> to read into an int, then push_back the int into the grades vector. You can either assume that there will be exactly 10 grades, or you can just keep reading grades until an error or end of file.

Then, you create a std::vector<student>. If you are not assuming that there will be exactly 10 grades, then instead of using operator>> to read student by student, you then use getline to read into a string like what you did. The trick is that after reading into the string, you then create a stringstream from the string, and then read from the stringstream into a student object, then use push_back to append it to the vector of student objects.

Well, I found out I was getting the values, but
every third iteration the program would just hang or crash. It gets out of the extract with values, but it hangs after "going to next person"