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AVerage help

chizzain (48)
I'm trying to get the average of 3 test scores in the code below but it won't work, how do I go about doing it?

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	friend std::ostream &operator<<(std::ostream &out, const Grade &s)
	{
		return out << "Name: "      << s.first << " "    << s.middle << " " << s.last      << std::endl
			<< "test1: "      << s.test1      << std::endl
			<< "test2: "  << s.test2  << std::endl
			<< "test3: "  << s.test3  << std::endl
			<< "average: "  << s.test1+s.test2+s.test3/3  << std::endl
			<< "Absences: "  << s.absence  << std::endl;
	}
};
Peter87 (11178)
You have to put parenthesis, same as in math.
(s.test1+s.test2+s.test3)/3
chizzain (48)
ok i do that and i get this error, heres my code:

error C2676: binary '/' : 'std::basic_string<_Elem,_Traits,_Ax>' does not define this operator or a conversion to a type acceptable to the predefined operator


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

struct Grade
{
	std::string last,
		first,
		middle,
		test1,
		test2,
		test3,
		absence;

	friend std::istream &operator>>(std::istream &in, Grade &s)
	{
		return in >> s.last >> s.first >> s.middle >> s.test1 >> s.test2 >> s.test3 >> s.absence;
	}
	friend std::ostream &operator<<(std::ostream &out, const Grade &s)
	{
		return out << "Name: "      << s.first << " "    << s.middle << " " << s.last      << std::endl
			<< "test1: "      << s.test1      << std::endl
			<< "test2: "  << s.test2  << std::endl
			<< "test3: "  << s.test3  << std::endl
			<< "average: "  << (s.test1+s.test2+s.test3)/3  << std::endl
			<< "Absences: "  << s.absence  << std::endl;
	}
};


void main ()
{
	std::vector<Grade> grades;

	{
		std::ifstream infile ("students.txt");
		Grade temp;
		while(infile >> temp)
		{
			grades.push_back(temp);
		}
	}

	for(size_t i = 0; i < grades.size(); ++i)
	{
		std::cout << grades[i] << std::endl;
	}
}
Peter87 (11178)
The test variables are strings. You can't divide a string. You probably want to make them some numerical type instead of string.
chizzain (48)
How?
Peter87 (11178)
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struct Grade
{
	std::string last,
	            first,
	            middle,
	            absence;
	double test1,
	       test2,
	       test3;
	...

Last edited on
SamuelAdams (1535)
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