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program blows up

Mar 27th, 2008

I know it has to do something with my main and around the "how many classes" but my program runs without any errors or warnings but blows up so I was wanting to know if someone could take a look at it.....

I know I havent worked on the gpa so that can be ignored for now....

my code:

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
#include <iostream>
#include <string>
using namespace std;
int Get_Name_and_Num_Classes(string prompt);
double Calculate_GPA(char grade, int number);
void Get_Letter_Grade(char grade);
int Convert_Let_to_Num(int number);
void Print_Results(string name, double gpa);
 
int main()
{
	string name;
	int count = 1;
	int classes, number = 0;
	char grade = 0;
	double gpa = 0.0;
 
	cout << "Programmed by Jim Johnson";
	cout << endl << endl << "Type xxx for the name to Exit";
 
	do
	{
		cout << endl << endl << "Enter the student's last name: ";
		name = Get_Name_and_Num_Classes("name");
 
		while (name != "xxx")
		{
			cout << endl << "How many classes taken: ";
			classes = Get_Name_and_Num_Classes("classes");
 
		}while (count <= classes)
 
		{
		cout << endl << endl << "Enter letter grade " << count << ": ";
		Get_Letter_Grade(grade);
		count ++;
		}
		//gpa = Calculate_GPA(grade, count);
		number = Convert_Let_to_Num(number);
		Print_Results(name, gpa);
	}while (name != "xxx");
 
	return 0;
}
 
int Get_Name_and_Num_Classes(string variable)
{
	int x = 0;
	cin >> x;
	return x;
 
}
 
void Get_Letter_Grade(char grade)
{
 
cin >> grade;
 
 
}
 
//calculate gpa here
 
int Convert_Let_to_Num(int number)
{
	char grade = 0;
	if ((grade == 'a') || (grade == 'A'))
	{
		number = 4;
	}
	if ((grade == 'b') || (grade == 'B'))
	{
		number = 3;
	}
	if ((grade == 'c') || (grade == 'C'))
	{
		number = 2;
	}
	if ((grade == 'd') || (grade == 'D'))
	{
		number = 1;
	}
	if ((grade == 'f') || (grade == 'F'))
	{
		number = 0;
	}
	return (number);
}
 
void Print_Results(string name, double gpa)
{
	cout << "Student " << name << " has a semester GPA of " << gpa;
}
#include <iostream>
#include <string>
using namespace std;
int Get_Name_and_Num_Classes(string prompt);
double Calculate_GPA(char grade, int number);
void Get_Letter_Grade(char grade);
int Convert_Let_to_Num(int number);
void Print_Results(string name, double gpa);

int main()
{
	string name;
	int count = 1;
	int classes, number = 0;
	char grade = 0;
	double gpa = 0.0;

	cout << "Programmed by Jim Johnson";
	cout << endl << endl << "Type xxx for the name to Exit";

	do
	{
		cout << endl << endl << "Enter the student's last name: ";
		name = Get_Name_and_Num_Classes("name");

		while (name != "xxx")
		{
			cout << endl << "How many classes taken: ";
			classes = Get_Name_and_Num_Classes("classes");

		}while (count <= classes)
		
		{
		cout << endl << endl << "Enter letter grade " << count << ": ";
		Get_Letter_Grade(grade);
		count ++;
		}
		//gpa = Calculate_GPA(grade, count);
		number = Convert_Let_to_Num(number);
		Print_Results(name, gpa);
	}while (name != "xxx");

	return 0;
}

int Get_Name_and_Num_Classes(string variable)
{
	int x = 0;
	cin >> x;
	return x;

}

void Get_Letter_Grade(char grade)
{
	
cin >> grade;
		
	
}

//calculate gpa here

int Convert_Let_to_Num(int number)
{
	char grade = 0;
	if ((grade == 'a') || (grade == 'A'))
	{
		number = 4;
	}
	if ((grade == 'b') || (grade == 'B'))
	{
		number = 3;
	}
	if ((grade == 'c') || (grade == 'C'))
	{
		number = 2;
	}
	if ((grade == 'd') || (grade == 'D'))
	{
		number = 1;
	}
	if ((grade == 'f') || (grade == 'F'))
	{
		number = 0;
	}
	return (number);
}

void Print_Results(string name, double gpa)
{
	cout << "Student " << name << " has a semester GPA of " << gpa;
}

output should be:

Programmed by <your name>

Type xxx for the name to exit

Enter the student's last name: Mickey
How many classes taken: 3

Enter letter grade 1: a
Enter letter grade 2: B
Enter letter grade 3: b

Student Mickey has a semester GPA of 3.33

Enter the student's last name: Goofy
How many classes taken: 5

Enter letter grade 1: c
Enter letter grade 2: C
Enter letter grade 3: d
Enter letter grade 4: b
Enter letter grade 5: a

Student Goofy has a semester GPA of 2.40

Enter the student's last name: Donald
How many classes taken: 2

Enter letter grade 1: c
Enter letter grade 2: B

Student Donald has a semester GPA of 2.50

Enter the student's last name: Minnie
How many classes taken: 4

Enter letter grade 1: A
Enter letter grade 2: A
Enter letter grade 3: B
Enter letter grade 4: A

Student Mickey has a semester GPA of 3.75

Enter the student's last name: xxx

Last edited by Ancient Dragon; Mar 27th, 2008 at 1:56 pm. Reason: add code tags

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Re: program blows up

Mar 27th, 2008

line 35: you need to pass variable grade by reference to that Get_Letter_Grade() can change its value. Then in main() you need to save all the graded in an array so that the GPA can be calculated.

line 39: the value of number is never set to anything so all it is passing to Convert_Let_to_Num() is the3 value 0 (line 14)

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Re: program blows up

Mar 27th, 2008

not allowed to use arrays

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Re: program blows up

Mar 27th, 2008

Ok, so another way to do it is to sum up all the grades and divide the the number of grades. Such as:

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while (count <= classes)
{
    number = Get_Letter_Grade(grade);
    number = Convert_Let_to_Num(number);
    sum = sum + number;
    count = count + 1;
}
GPA = sum / classes;
while (count <= classes)
{
    number = Get_Letter_Grade(grade);
    number = Convert_Let_to_Num(number);
    sum = sum + number;
    count = count + 1;
}
GPA = sum / classes;

Last edited by Ancient Dragon; Mar 27th, 2008 at 2:23 pm.

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Re: program blows up

Mar 27th, 2008

still blowing up.....

 Help with Code Tags 
 c++ Syntax (Toggle Plain Text) 
 
#include <iostream>
#include <string>
using namespace std;
int Get_Name_and_Num_Classes(string prompt);
double Calculate_GPA(char grade, int number);
void Get_Letter_Grade(char grade);
int Convert_Let_to_Num(int number);
void Print_Results(string name, double gpa);
 
int main()
{
	string name;
	int classes, sum, count = 1, number = 0;
	char grade = 0;
	double gpa = 0.0;
 
	cout << "Programmed by Jim Johnson";
	cout << endl << endl << "Type xxx for the name to Exit";
 
	do
	{
		cout << endl << endl << "Enter the student's last name: ";
		name = Get_Name_and_Num_Classes("name");
 
		while (name != "xxx")
		{
			cout << endl << "How many classes taken: ";
			classes = Get_Name_and_Num_Classes("classes");
 
		}while (count <= classes)
 
		{
		cout << endl << endl << "Enter letter grade " << count << ": ";
		Get_Letter_Grade(grade);
		number = Convert_Let_to_Num(number);
		sum = sum + number;
		count = count + 1;
		count ++;
		}
		//gpa = Calculate_GPA(grade, count);
		number = Convert_Let_to_Num(number);
		Print_Results(name, gpa);
	}while (name != "xxx");
 
	return 0;
}
 
int Get_Name_and_Num_Classes(string variable)
{
	int x = 0;
	cin >> x;
	return x;
 
}
 
void Get_Letter_Grade(char grade)
{
 
cin >> grade;
 
 
}
 
//calculate gpa here
 
int Convert_Let_to_Num(int number)
{
	char grade = 0;
	if ((grade == 'a') || (grade == 'A'))
	{
		number = 4;
	}
	if ((grade == 'b') || (grade == 'B'))
	{
		number = 3;
	}
	if ((grade == 'c') || (grade == 'C'))
	{
		number = 2;
	}
	if ((grade == 'd') || (grade == 'D'))
	{
		number = 1;
	}
	if ((grade == 'f') || (grade == 'F'))
	{
		number = 0;
	}
	return (number);
}
 
void Print_Results(string name, double gpa)
{
	cout << "Student " << name << " has a semester GPA of " << gpa;
}
#include <iostream>
#include <string>
using namespace std;
int Get_Name_and_Num_Classes(string prompt);
double Calculate_GPA(char grade, int number);
void Get_Letter_Grade(char grade);
int Convert_Let_to_Num(int number);
void Print_Results(string name, double gpa);

int main()
{
	string name;
	int classes, sum, count = 1, number = 0;
	char grade = 0;
	double gpa = 0.0;

	cout << "Programmed by Jim Johnson";
	cout << endl << endl << "Type xxx for the name to Exit";

	do
	{
		cout << endl << endl << "Enter the student's last name: ";
		name = Get_Name_and_Num_Classes("name");

		while (name != "xxx")
		{
			cout << endl << "How many classes taken: ";
			classes = Get_Name_and_Num_Classes("classes");

		}while (count <= classes)
		
		{
		cout << endl << endl << "Enter letter grade " << count << ": ";
		Get_Letter_Grade(grade);
		number = Convert_Let_to_Num(number);
		sum = sum + number;
		count = count + 1;
		count ++;
		}
		//gpa = Calculate_GPA(grade, count);
		number = Convert_Let_to_Num(number);
		Print_Results(name, gpa);
	}while (name != "xxx");

	return 0;
}

int Get_Name_and_Num_Classes(string variable)
{
	int x = 0;
	cin >> x;
	return x;

}

void Get_Letter_Grade(char grade)
{
	
cin >> grade;
		
	
}

//calculate gpa here

int Convert_Let_to_Num(int number)
{
	char grade = 0;
	if ((grade == 'a') || (grade == 'A'))
	{
		number = 4;
	}
	if ((grade == 'b') || (grade == 'B'))
	{
		number = 3;
	}
	if ((grade == 'c') || (grade == 'C'))
	{
		number = 2;
	}
	if ((grade == 'd') || (grade == 'D'))
	{
		number = 1;
	}
	if ((grade == 'f') || (grade == 'F'))
	{
		number = 0;
	}
	return (number);
}

void Print_Results(string name, double gpa)
{
	cout << "Student " << name << " has a semester GPA of " << gpa;
}

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Re: program blows up

Mar 27th, 2008

I tried putting in by reference and this is what I got.....

 Help with Code Tags 
 c++ Syntax (Toggle Plain Text) 
 
#include <iostream>
#include <string>
using namespace std;
int Get_Name_and_Num_Classes(string prompt);
double Calculate_GPA(char& grade, int number);
void Get_Letter_Grade(char grade);
int Convert_Let_to_Num(int number);
void Print_Results(string name, double gpa);
 
int main()
{
	string name;
	int classes, sum = 0, count = 1, number = 0;
	char grade = 0;
	double gpa = 0.0;
 
	cout << "Programmed by Jim Johnson";
	cout << endl << endl << "Type xxx for the name to Exit";
 
	do
	{
		cout << endl << endl << "Enter the student's last name: ";
		name = Get_Name_and_Num_Classes("name");
 
		while (name != "xxx")
		{
			cout << endl << "How many classes taken: ";
			classes = Get_Name_and_Num_Classes("classes");
 
		}while (count <= classes)
 
		{
		cout << endl << endl << "Enter letter grade " << count << ": ";
		Get_Letter_Grade(grade);
		number = Convert_Let_to_Num(number);
		sum = sum + number;
		count = count + 1;
		count ++;
		}
		//gpa = Calculate_GPA(grade, count);
		number = Convert_Let_to_Num(number);
		Print_Results(name, gpa);
	}while (name != "xxx");
 
	return 0;
}
 
int Get_Name_and_Num_Classes(string variable)
{
	int x = 0;
	cin >> x;
	return x;
 
}
 
void Get_Letter_Grade(char& grade)
{
 
cin >> grade;
 
 
}
 
//calculate gpa here
 
int Convert_Let_to_Num(int number)
{
	char grade = 0;
	if ((grade == 'a') || (grade == 'A'))
	{
		number = 4;
	}
	if ((grade == 'b') || (grade == 'B'))
	{
		number = 3;
	}
	if ((grade == 'c') || (grade == 'C'))
	{
		number = 2;
	}
	if ((grade == 'd') || (grade == 'D'))
	{
		number = 1;
	}
	if ((grade == 'f') || (grade == 'F'))
	{
		number = 0;
	}
	return (number);
}
 
void Print_Results(string name, double gpa)
{
	cout << "Student " << name << " has a semester GPA of " << gpa;
}
#include <iostream>
#include <string>
using namespace std;
int Get_Name_and_Num_Classes(string prompt);
double Calculate_GPA(char& grade, int number);
void Get_Letter_Grade(char grade);
int Convert_Let_to_Num(int number);
void Print_Results(string name, double gpa);

int main()
{
	string name;
	int classes, sum = 0, count = 1, number = 0;
	char grade = 0;
	double gpa = 0.0;

	cout << "Programmed by Jim Johnson";
	cout << endl << endl << "Type xxx for the name to Exit";

	do
	{
		cout << endl << endl << "Enter the student's last name: ";
		name = Get_Name_and_Num_Classes("name");

		while (name != "xxx")
		{
			cout << endl << "How many classes taken: ";
			classes = Get_Name_and_Num_Classes("classes");

		}while (count <= classes)
		
		{
		cout << endl << endl << "Enter letter grade " << count << ": ";
		Get_Letter_Grade(grade);
		number = Convert_Let_to_Num(number);
		sum = sum + number;
		count = count + 1;
		count ++;
		}
		//gpa = Calculate_GPA(grade, count);
		number = Convert_Let_to_Num(number);
		Print_Results(name, gpa);
	}while (name != "xxx");

	return 0;
}

int Get_Name_and_Num_Classes(string variable)
{
	int x = 0;
	cin >> x;
	return x;

}

void Get_Letter_Grade(char& grade)
{
	
cin >> grade;
		
	
}

//calculate gpa here

int Convert_Let_to_Num(int number)
{
	char grade = 0;
	if ((grade == 'a') || (grade == 'A'))
	{
		number = 4;
	}
	if ((grade == 'b') || (grade == 'B'))
	{
		number = 3;
	}
	if ((grade == 'c') || (grade == 'C'))
	{
		number = 2;
	}
	if ((grade == 'd') || (grade == 'D'))
	{
		number = 1;
	}
	if ((grade == 'f') || (grade == 'F'))
	{
		number = 0;
	}
	return (number);
}

void Print_Results(string name, double gpa)
{
	cout << "Student " << name << " has a semester GPA of " << gpa;
}

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Re: program blows up

Mar 27th, 2008

line 49: Get_Name_and_Num_Classes() -- that seems to be a misnamed function. Your program expects it to return a string from line 24 but it actually returns an integer. You could hack it to return both a string and an integer but it would be a lot better to use two different functions -- GetNumClasses() and GetName(). If you do that then there will be no confusion about what it should return. And neither function needs a parameter.

line 36 of your most recent attempt is incorrect. Pass grade as the parameter, not number.

Last edited by Ancient Dragon; Mar 27th, 2008 at 3:02 pm.

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Re: program blows up

Mar 27th, 2008

we are not allowed to do that either....here let me give u the instructions for this program so you might have a better understanding.

Write a program to compute a student’s GPA for one semester. It should ask the user for the student’s last name, and how many classes were taken during the semester. It will then ask the user to type in the letter grade for each class and print the GPA to the screen.

The program should continue doing this until the user types an xxx for the last name.
Program Requirements
• To make the program easier, assume all classes are 3 credits.
• There should be two digits of precision
• You should have the following functions:
• Get_Name_and_Num_Classes - This function asks the user to type in their name and the number of classes taken
• Calculate_GPA - This function computes GPA. It does this by looping. It call Get_Letter_Grade to allow the user to enter a valid letter grade and then it calls Convert_Let_to_Num. It uses this information to compute the GPA. It returns the GPA. (you should be able to determine the formal parameters)
• Get_Letter_Grade – This function is a void function. It asks the user to type in a letter grade, and then makes sure that the letter grade is valid. It must be an A, B, C, D, or F. You should be able to determine the formal parameters.
• Convert_Let_to_Num – Takes in a letter grade and converts it to its number equivalent (A–4, B–3, C–2, D–1, F–0) It should return the number equivalent.
• Print_Results - This prints all results to the screen. It should not return a value.

here is my code:

 Help with Code Tags 
 c++ Syntax (Toggle Plain Text) 
 
#include <iostream>
#include <string>
using namespace std;
int Get_Name_and_Num_Classes(string prompt);
double Calculate_GPA(char& grade, int number);
void Get_Letter_Grade(char grade);
int Convert_Let_to_Num(int number);
void Print_Results(string name, double gpa);
 
int main()
{
	string name;
	int classes, sum = 0, count = 1, number = 0;
	char grade = 0;
	double gpa = 0.0;
 
	cout << "Programmed by Jim Johnson";
	cout << endl << endl << "Type xxx for the name to Exit";
 
	do
	{
		cout << endl << endl << "Enter the student's last name: ";
		name = Get_Name_and_Num_Classes("name");
 
		while (name != "xxx")
		{
			cout << endl << "How many classes taken: ";
			classes = Get_Name_and_Num_Classes("classes");
 
		}while (count <= classes)
 
		{
		cout << endl << endl << "Enter letter grade " << count << ": ";
		Get_Letter_Grade(grade);
		number = Convert_Let_to_Num(grade);
		sum = sum + number;
		count = count + 1;
		count ++;
		}
		//gpa = Calculate_GPA(grade, count);
		number = Convert_Let_to_Num(number);
		Print_Results(name, gpa);
	}while (name != "xxx");
 
	return 0;
}
 
int Get_Name_and_Num_Classes(string variable)
{
	int x = 0;
	cin >> x;
	return x;
 
}
 
void Get_Letter_Grade(char& grade)
{
 
cin >> grade;
 
 
}
 
//calculate gpa here
 
int Convert_Let_to_Num(int number)
{
	char grade = 0;
	if ((grade == 'a') || (grade == 'A'))
	{
		number = 4;
	}
	if ((grade == 'b') || (grade == 'B'))
	{
		number = 3;
	}
	if ((grade == 'c') || (grade == 'C'))
	{
		number = 2;
	}
	if ((grade == 'd') || (grade == 'D'))
	{
		number = 1;
	}
	if ((grade == 'f') || (grade == 'F'))
	{
		number = 0;
	}
	return (number);
}
 
void Print_Results(string name, double gpa)
{
	cout << "Student " << name << " has a semester GPA of " << gpa;
}
#include <iostream>
#include <string>
using namespace std;
int Get_Name_and_Num_Classes(string prompt);
double Calculate_GPA(char& grade, int number);
void Get_Letter_Grade(char grade);
int Convert_Let_to_Num(int number);
void Print_Results(string name, double gpa);

int main()
{
	string name;
	int classes, sum = 0, count = 1, number = 0;
	char grade = 0;
	double gpa = 0.0;

	cout << "Programmed by Jim Johnson";
	cout << endl << endl << "Type xxx for the name to Exit";

	do
	{
		cout << endl << endl << "Enter the student's last name: ";
		name = Get_Name_and_Num_Classes("name");

		while (name != "xxx")
		{
			cout << endl << "How many classes taken: ";
			classes = Get_Name_and_Num_Classes("classes");

		}while (count <= classes)
		
		{
		cout << endl << endl << "Enter letter grade " << count << ": ";
		Get_Letter_Grade(grade);
		number = Convert_Let_to_Num(grade);
		sum = sum + number;
		count = count + 1;
		count ++;
		}
		//gpa = Calculate_GPA(grade, count);
		number = Convert_Let_to_Num(number);
		Print_Results(name, gpa);
	}while (name != "xxx");

	return 0;
}

int Get_Name_and_Num_Classes(string variable)
{
	int x = 0;
	cin >> x;
	return x;

}

void Get_Letter_Grade(char& grade)
{
	
cin >> grade;
		
	
}

//calculate gpa here

int Convert_Let_to_Num(int number)
{
	char grade = 0;
	if ((grade == 'a') || (grade == 'A'))
	{
		number = 4;
	}
	if ((grade == 'b') || (grade == 'B'))
	{
		number = 3;
	}
	if ((grade == 'c') || (grade == 'C'))
	{
		number = 2;
	}
	if ((grade == 'd') || (grade == 'D'))
	{
		number = 1;
	}
	if ((grade == 'f') || (grade == 'F'))
	{
		number = 0;
	}
	return (number);
}

void Print_Results(string name, double gpa)
{
	cout << "Student " << name << " has a semester GPA of " << gpa;
}

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Re: program blows up

Mar 27th, 2008

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int Convert_Let_to_Num(int number)
{
	char grade = 0;
	if ((grade == 'a') || (grade == 'A'))
	{
		number = 4;

Q1: What answer do you expect given that you set grade to 0, then proceed to test it against various letters.

Q2: If all you do is assign 1 to 4 to number, what do you think happens to the value you pass as a parameter?

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Re: program blows up

#10

Mar 27th, 2008

line 5: the parameter prompt is misnamed -- should be name and passed by reference int Get_Name_and_Num_Classes(string& name); then change line 24 to use the above function prototype and change the function beginning at line 45 to do as instructed storing the name the the user typed into the parameter name and returning the number of classes. The function you wrote does not do that.

you can delete lines 23 and 24 because that info belongs in function Get_Name_and_Num_Classes().

I think the do loop lines 21-44 can be abbreviated

 Help with Code Tags 
 C++ Syntax (Toggle Plain Text) 
std::string name;
int numClasses = 0;
int sum = 0;
do 
{
    numClasses = Get_Name_and_Num_Classes(name);
    if( name != "xxx" )
    {
         GPA = Calculate_GPA(numClasses);
    }
} while( name != "xxx");
std::string name;
int numClasses = 0;
int sum = 0;
do 
{
    numClasses = Get_Name_and_Num_Classes(name);
    if( name != "xxx" )
    {
         GPA = Calculate_GPA(numClasses);
    }
} while( name != "xxx");