Error Description

This is a discussion on Error Description within the C++ Programming forums, part of the General Programming Boards category; Hello, Can somebody tell me what this error means? : error C2676: binary '*' : 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' ...

  1. #1
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    Error Description

    Hello,
    Can somebody tell me what this error means?

    : error C2676: binary '*' : 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' does not define this operator or a conversion to a type acceptable to the predefined operator

    I'm trying to create a function that calculates the cost of a tank of gas according to user input. I'm using multiple files so I'll show a snippet of the parts I've entered.

    Code:
    #ifndef _HEADER_H
    #define _HEADER_H
    #include<iostream>
    #include<string>
    
    using namespace std;
    
    enum VehicleType{Automobile,Airplane,Train};
    enum FuelKind{Gasoline,JetFuel,Diesel};
    
    //==========================================
    
    struct VehicleInfo
    {
    	string RateOfSpeed;
    	string FuelCost;
    	string TankSize;
    	string mpg;
    };
    
    //============================================
    
    class CVehicle
    {
    protected:
    	VehicleInfo vinfo;
    	VehicleType type;
    	FuelKind ftype;
    	double CostFullLoad;  //new here
    
    public:
    	CVehicle(VehicleInfo, VehicleType t,FuelKind f);
    	CVehicle(){}               
    	void GetInfo();
    	void CalcFullLoadCost();  //new here
    	virtual void WriteData();
    };
    
    #endif
    That was the Header file.

    Code:
    void CVehicle::GetInfo()
    {
    	cout<<"\nEnter How Fast: ";
    	cin>>vinfo.RateOfSpeed;
    	cout<<"\nEnter Cost Per Gallon: ";
    	cin>>vinfo.FuelCost;
    	cout<<"\nHow many gallons will tank hold: ";
    	cin>>vinfo.TankSize;
    	cout<<"\nHow many miles per gallon: ";
    	cin>>vinfo.mpg;
    }
    
    //============================================
    
    //the error is on this line 
    
    void CVehicle::CalcFullLoadCost()  //new
    { CostFullLoad=(vinfo.TankSize * vinfo.FuelCost); }//new
    
    
    //============================================
    I am using a structure if that makes a difference. It doesn't seem to recognize the multiplication operator. Thank you for any help! MCorn

  2. #2
    moi
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    the error means exactly what it says: you cant multiply strings. did you want to convert the strings to numbers first and then mulitply them? or maybe store them as numbers in the first place?
    hello, internet!

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    Smile

    Thank you Moi ! Is there some how to accomplish this with data casting...or something more on a beginner level? I impressed with your knowledge, however, you may as well be speaking Egyptian to me. I'd understand that just a well!

  4. #4
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    Why not just make these data members integers (or floats) in the first place? Is there any specific reason why you declared them as strings?

    Code:
    struct VehicleInfo
    {
    	double RateOfSpeed;
    	double FuelCost;
    	double TankSize;
    	double mpg;
    };

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    I guess the only reason I did that is because....I don't know ...I've been at it too long....or "idiot" comes to mind! Thanks for the help!

  6. #6
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    Originally posted by mcorn
    I guess the only reason I did that is because....I don't know ...I've been at it too long....or "idiot" comes to mind! Thanks for the help!
    Don't worry-- I spent my entire saturday night debugging. Oh what a wonderful life I lead.

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