C++

Operator Overloading in C++

Operating overloading allows you to pass different variable types to the same function and produce different results. In this article Ben gives us the low-down on operator overloading in C++.

Author Info:

By: Ben Watson

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December 08, 2002

TABLE OF CONTENTS:

· Operator Overloading in C++
· Definition
· Overloading =
· Overloading
· Matrix Multiplication - Overloading * Again
· Putting It All Together
· Conclusion

Operator Overloading in C++ - Putting It All Together
(Page 6 of 7 )

To demonstrate the Matrix class and its overloaded operators, I've written a sample main() as well as some helper functions that will run the class through its paces:

//the functions fill in a matrix with random values--they are type-specific
void init_matrix(Matrix<int>& m) {
for (int r=0;r<m.GetRows();r++)
for (int c=0;c<m.GetCols();c++)
m[r][c]=rand()%5+1;
}

void init_matrix(Matrix<__int64>& m) {
for (int r=0;r<m.GetRows();r++)
for (int c=0;c<m.GetCols();c++)
m[r][c]=rand()%100000+1;
}

void init_matrix(Matrix<float>& m, int precision) {
for (int r=0;r<m.GetRows();r++)
for (int c=0;c<m.GetCols();c++) {
float dec=float(rand()%precision)/precision;
m[r][c]=float(rand()%5)+1.0+dec;
}
}

int _tmain(int argc, _TCHAR* argv[])
{
srand((unsigned)time(NULL));

//save/load from file7
Matrix<int> a(5,5);
init_matrix(a);
a[0][0]=-13;
a[1][1]=-13;
cout << "Writing to file from Matrix a:" <<endl;
cout << a<<endl;
ofstream of;
of.open("test.txt");
of << a<<endl;
of.close();
ifstream iff("test.txt");
if (!iff) {
cout << "Error opening file"<<endl;
return 1;
}
Matrix<int> b;
cout << "Reading from file into Matrix b:"<<endl;
iff >> b;
iff.close();
cout <<endl;
cout << b<<endl;

cout <<"Press any key to continue..."<<endl;
getchar();

//add two floating-point matrices
Matrix<float> c(3,2);
init_matrix(c,100);
cout <<"Matrix c:"<<endl<< c<<endl;
Matrix<float> d(3,2);
init_matrix(d,100);
cout << "Matrix d:"<<endl<<d<<endl;
cout << "c+d:"<<endl<<c+d<<endl;

cout <<"Press any key to continue..."<<endl;
getchar();

//scale a floating-point matrix
Matrix<float> e(10,10);
init_matrix(e,1);
float scalar=-1.5;
cout << "Matrix e:" << endl<<e<<endl;
cout << "Scalar: "<<scalar<<endl;
cout << "e * scalar:"<<endl<<e*scalar<<endl;

cout <<"Press any key to continue..."<<endl;
getchar();

//matrix-product
Matrix<__int64> f(3,5);
Matrix<__int64> g(5,6);
init_matrix(f);
init_matrix(g);
cout <<"Matrix f:"<<endl<<f<<endl;
cout <<"Matrix g:"<<endl<<g<<endl;
cout <<"f*g:"<<endl<<f*g<<endl;

cout <<"Press any key to continue..."<<endl;
getchar();

return 0;
}

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