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aliens112 (13)
hello,i'm new to programming and I have the code:blocks ide with mingw compiler. It worked fine by now but I just started making a little bit more serious code with loops and so and something went wrong. My program is compiled just fine but when I type something it closes. I get to the point of typing "YES" and after that whatever i type the program closes itself.

Here's my code
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#include <iostream>
#include <string>
int main()
{
	using namespace std;
	/* Determinate Percentage taken into account for each grade
	for an english,math and science student
	*/
	const float ENGLISH_MIDTERM_PERCAENTAGE = 0.25;
	const float ENGLISH_FINALEXAM_PERCENTAGE = 0.25;
	const float ENGLISH_RESEARCH_PERCENTAGE = 0.30;
	const float ENGLISH_PRESENTATION_PERCENTAGE = 0.20;
	const float MATH_MIDTERM_PERCENTAGE = 0.50;
	const float MATH_FINALEXAM_PERCENTAGE = 0.50;
	const float SCIENCE_MIDTERM_PERCENTAGE = 0.40;
	const float SCIENCE_FINALEXAM_PERCENTAGE = 0.40;
	const float SCIENCE_RESEARCH_PERCENTAGE = 0.20;
	int midterm ;
	int finalExamGrade ;
	int research ;
	int presentation ;

	float finalNumericGrade = 0;
	char finalLetterGrade;
	char response[256];
	string moreGradesToCalculate;
	cout<<"Do you want to calculate a grade? ";
	cin>>moreGradesToCalculate;
	for(int i=0;i<moreGradesToCalculate.length();i++)
	{
	    moreGradesToCalculate[i]= toupper (moreGradesToCalculate[i]);
	}
	while (moreGradesToCalculate=="YES")
	{

	cout<<"Enter student type: English, Math or Science: "
	<<"English =1 , Math = 2, Sciece = 3"<<endl;
	cin.getline (response,256);
	if (strlen (response)==0){
	    cout<<"You must enter a student type";
	    return 1;
	}
	if ((atoi (response)<1) | (atoi (response) >3))
	{
	    cout<< response<< " - is not a valid student type";
	    return 1;
	}
	switch (atoi (response))
	{
	    //Case 1  - English Student
	    case 1:
	    cout<<"Enter the midterm grade: ";
	    cin.getline (response,256);
	    midterm= atoi(response);
	    cout<<"Enter the Final Examination grade: ";
	    cin.getline (response,256);
	    finalExamGrade = atoi (response);
	    cout<<"Enter the Research grade: ";
	    cin.getline (response,256);
	    research = atoi (response);
	    cout<<"Enter the presentation grade: ";
	    cin.getline (response,256);
	    presentation = atoi (response);


	    finalNumericGrade = midterm * ENGLISH_MIDTERM_PERCAENTAGE + finalExamGrade* ENGLISH_FINALEXAM_PERCENTAGE +
	    research* ENGLISH_RESEARCH_PERCENTAGE + presentation * ENGLISH_PRESENTATION_PERCENTAGE;
	    if (finalNumericGrade >= 93)
	    finalLetterGrade = 'A' ;
	    else
	    if ((finalNumericGrade >=85) & (finalNumericGrade < 93))
	    finalLetterGrade = 'B';
        else
        if
        (( finalNumericGrade >= 78 ) & (finalNumericGrade < 85))
        finalLetterGrade = 'C';
        else
        if (( finalNumericGrade >= 70) & ( finalNumericGrade < 78))
        finalLetterGrade = 'D';
        else
        if ( finalNumericGrade <70)
        finalLetterGrade = 'F';
        cout<<" *** ENGLISH STUDENT *** " <<endl<<endl;
        cout<<"Midterm grade is: "<<midterm<<endl;
        cout<<"Final Examination grade is : " <<finalExamGrade<<endl;
        cout<<"Research Grade is : " <<research<<endl;
        cout<<"Presentation grade is : "<<presentation<<endl;
        cout<<"Final Numeric Grade is: "<<finalNumericGrade<<endl;
        cout<<"Final Letter Grade is : "<<finalLetterGrade <<endl;
        break;
        //Case 2 is Math Student
        case 2:
        cout<<"Enter midterm grade : ";
        cin.getline (response,256);
        midterm = atoi (response);
        cout<<"Enter final examination grade : ";
        cin.getline (response,256);
        finalExamGrade = atoi (response);
        finalNumericGrade = (midterm * MATH_MIDTERM_PERCENTAGE)+( finalExamGrade * MATH_FINALEXAM_PERCENTAGE);
        if (finalNumericGrade >= 93)
	    finalLetterGrade = 'A' ;
	    else
	    if ((finalNumericGrade >=85) & (finalNumericGrade < 93))
	    finalLetterGrade = 'B';
        else
        if
        (( finalNumericGrade >= 78 ) & (finalNumericGrade < 85))
        finalLetterGrade = 'C';
        else
        if (( finalNumericGrade >= 70) & ( finalNumericGrade < 78))
        finalLetterGrade = 'D';
        else
        if ( finalNumericGrade <70)
        finalLetterGrade = 'F';
        cout<<" *** Mathematics Student *** "<<endl<<endl;
        cout<<"Midterm Grade : "<<midterm<<endl;
        cout<<"Final Examination Grade : "<<finalExamGrade<<endl;
        cout<<"Final Numeric Grade : "<<finalNumericGrade<<endl;
        cout<<"Final Letter Grade : " <<finalLetterGrade<<endl;
        break;
        //Case 3 Is Science Student
        case 3:
        cout<<"Enter Midterm Grade : ";
        cin.getline (response,256);
        midterm = atoi (response);
        cout<<"Enter Final Examination Grade : ";
        cin.getline (response,256);
        finalExamGrade = atoi (response);
        cout<<"Enter Research Grade : ";
        cin.getline (response,256);
        research = atoi(response);
        finalNumericGrade = midterm * SCIENCE_MIDTERM_PERCENTAGE + finalExamGrade * SCIENCE_FINALEXAM_PERCENTAGE
        + research* SCIENCE_RESEARCH_PERCENTAGE;
        if (finalNumericGrade >= 93)
	    finalLetterGrade = 'A' ;
	    else
	    if ((finalNumericGrade >=85) & (finalNumericGrade < 93))
	    finalLetterGrade = 'B';
        else
        if
        (( finalNumericGrade >= 78 ) & (finalNumericGrade < 85))
        finalLetterGrade = 'C';
        else
        if (( finalNumericGrade >= 70) & ( finalNumericGrade < 78))
        finalLetterGrade = 'D';
        else
        if ( finalNumericGrade <70)
        finalLetterGrade = 'F';
        cout<<" *** Science Student *** "<<endl<<endl;
        cout<<" Midterm Grade : " <<midterm<<endl;
        cout<<"Final Examamination Grade : "<<finalExamGrade<<endl;
        cout<<"Research Grade : "<<research<<endl;
        cout<<"Final Numeric Grade : "<<finalNumericGrade<<endl;
        cout<<"Final Letter Grade : "<<finalLetterGrade<<endl;
        default:
        cout <<response<<" is not a valid student type...";
        return 1;
	}
	cout<<endl<<endl<<"Do you have another grade to calculate? ";
	cin>>moreGradesToCalculate;
	for (int i = 0;i<moreGradesToCalculate.length();i++)
	{moreGradesToCalculate[i]=toupper (moreGradesToCalculate[i]);
	}
	}

	return 0;


}

aliens112 (13)
I'm pretty sure that the problem lies somewhere here
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while (moreGradesToCalculate=="YES")
	{

	cout<<"Enter student type: English, Math or Science: "
	<<"English =1 , Math = 2, Sciece = 3"<<endl;
	cin.getline (response,256);
	if (strlen (response)==0){
	    cout<<"You must enter a student type";
	    return 1;
	}


cus as I execute the program it just skips the first cin and it looks like the user pressed enter without typing anything. Maybe it's a compiler prblm. :(
Duthomhas (13206)
You are mixing formatted and unformatted input.
See here http://www.cplusplus.com/forum/articles/6046/

Remember, get user input using getline(), then parse it. Don't mix cin >> x; with getline( cin, s );.

Hope this helps.
aliens112 (13)
i'm a real newbie so I hope my question won't annoy you :(.
but Duoas what do u mean by formatted and unformatted?
do you mean that instead of
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cin.getline (response[256])
cin>>response

i should use
getline(cin, input) ;
so my code will be something like
getline(cin, response) ;
?
Last edited on
Duthomhas (13206)
Yes. Using cin >> response; leaves everything that doesn't go into 'response' in the input buffer, including the newline left there when the user pressed Enter.

Using getline( cin, response ); reads everything the user typed, up-to-and-including the newline (or Enter key), and stores all the characters except the newline in the string. You can then figure out what to do with the string.

For example:
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#include <iostream>
#include <sstream>
#include <string>
using namespace std;

int getint( istream& ins, int result = 0 )
  {
  string s;
  getline( ins, s );
  istringstream ss( s );
  ss >> result;
  return result;
  }

int main()
  {
  int age;
  string name;

  cout << "How old are you? " << flush;
  age = getint( cin );

  cout << "What is your name? " << flush;
  getline( cin, name );

  cout << name << " is " << age << " years old.\n";
  return 0;
  }

Hope this helps.
aliens112 (13)
Duoas thanks a lot. although I don't 100% get what you meant in your code I managed to get mine working.
here's what I did. I changed the way the program handled the user input for the string "moreGradesToCalculate". From what I got getline (cin,variable); is meant to handle only strings cus I tried changing cin.getline(response,256) into getline(cin,response) and response is a char and I got an error. But again I might have made a mistake as I'm not very familiar with the syntax.
So Duoas you basically suggest me to use getline(cin,string) for strings in all cases right?

Thanks a lot for your help.
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