Question

创建一个多项式对象，提供以下文件
出于某种原因，当我在文件中阅读时：

它不会正确写入对象，例如第一个数字是多少个项，正确读取下一个数字3是系数，下一个数字5是指数。登记/> 数字读入正确但不会写入coeff和expon对象。这里没有提供的代码是由老师编写的，无论如何都非常简单，所以我不会包含它。

    #include <cstdlib>  
    #include <iostream>  
    #include <fstream>  
    #include <math.h>  
    #include <string>  
    using namespace std;  

    class Term
    {
    private:
       float coeff;
   int expon;

    public:
   Term();                  // --- Creates empty Term
   Term(float c, int e);    // --- Creates Term object with coeff. c 
 //and expon. e
   float getCoeff(void);    // --- returns coeff of term
   int getExpon(void);      // --- returns expon of term
   void setCoeff(float c);  // --- sets term's coeff. to c
   void setExpon(int c);    // --- sets term's expon to c
    }; 
    class Poly
    {
    public:
//Constructors
Poly();                  // creates empty polynomial
Poly(const Poly &poly);  // copy constructor
~Poly();        // destructor free dynamically allocate ptrs.

//Member Functions
void insertTerm(Term t); // inserts Term t into polynomial

//Accessors
int getNumTerms(void);   // returns number of terms in array
Term getTerm(int index); // returns term at index

//Mutators
void setNumTerms(int numberOfTerms);

//Overloaded Operators
Poly& operator = (const Poly& rightSide);//overloaded assignment operator
float operator () (float x);

    private:
int numTerms;            // number of terms in polynomial
int maxItems;            // array capacity
Term *terms;             // dynamically allocated array of terms
    };

    //Overloaded Operators for Poly Class
    ostream& operator << (ostream& outFile, Poly& op1);
    istream& operator >> (istream& inFile, Poly& op1);
    Poly operator + (Poly& op1, Poly& op2);

    //Functions
    void error(string msg = "ERROR\n", int errorCode = 1, bool doExit = true);

    int main(int argc, char* argv[])
    {
//open file
ifstream inFile;
inFile.open("test1.txt");
if (inFile.fail())
{
    cout << "open file error " << argv[argc - 1] << endl;
    exit(1);
}

Poly f;
Poly g;
Poly p;

int value (0); // value of x for evaluation
inFile >> f;
inFile >> g;

cout << "F(x) =  " << f << endl;
cout << "G(x) =  " << g << endl;

// make copies of the polynomials
Poly temp1(f);
Poly temp2(g);

// add polynomials f and g
p = f + g;
cout << "\nP(x) = (F + G)(x) = " << p << endl;

// read in a value for X
inFile >> value;

// evaluate the polynomial
cout << "P(" << value << ") = " << p(value) << endl << endl;

// swap temp1 and temp2 - shouldn't change f & g
Poly temp3(temp2);
temp2 = temp1;
temp1 = temp3;

// Insert a new term 8x^6
temp1.insertTerm(Term(8,6));

cout << "temp1(x) is same as 8x^6 + G(x) or " << temp1 << endl;
cout << "temp2(x) is same as F(x) or " << temp2 << endl;
cout << "temp3(x) is same as G(x) or " << temp3 << endl << endl;

cout << "Original functions were:" << endl;
cout << "F(x) =  " << f << endl;
cout << "G(x) =  " << g << endl;

inFile.close();
return 0;
    }

    /***********************************************************************
    * overloaded >> operator that reads an entire polynomial into an array
    * of Terms in the proper order.
    ***********************************************************************/
    istream& operator >> (istream& inFile, Poly& op1)
    {
int numTerms;
int expon;
float coeff;
int i = 0;

//get number of terms
inFile >> numTerms;
if (numTerms < 1)
    error("numTerms < 1\n", 2);
else
    op1.setNumTerms(numTerms);

//read in terms
while (i < op1.getNumTerms())
{
    //get coefficient check for valid term
    inFile >> coeff;
    if (inFile.fail())
    {
        error("inFile.fail() -- coeff\n", 3);
        exit(1);
    }
    cerr << op1.getTerm(i).getCoeff() << endl;
    op1.getTerm(i).setCoeff(coeff);
    cerr << op1.getTerm(i).getCoeff() << endl;

    //get exponent and check for valid term
    inFile >> expon;
    if (inFile.fail())
    {
        error("inFile.fail() -- expon\n", 4);
        exit(2);
    }
    op1.getTerm(i).setExpon(expon);
    i++;
}
i = op1.getNumTerms();
op1.getTerm(i).setCoeff(0);

return inFile;
    }

    /*****************************************************************************
    * error function produces error code
    ****************************************************************************/
    void error(string msg, int errorCode, bool doExit)
    {
cout << "*** ERROR ***\n"
     << msg << endl
     << "*** END ERROR ***\n";
if (doExit == true)
    exit(errorCode);

}

mutator功能不正常？

0 个答案: