how to use operator overloading and catch invalid input

skyluke · 11-09-2010, 09:56 AM

#include <iostream>
#include <iomanip>
#include <string>
#include <sstream>
#include <complex>

using namespace std;

const char openParen = '(';
const char closeParen = ')';
const char iChar = 'i';
const string ops("+-*/");
const string signs("-+");
const int negPos[] = { -1, 1 };

int main(int argc, char *argv[]) {
complex<float> *c1, *c2, result;
float a, b, c, d;
char opChar, lp, rp, signChar, i;
size_t op, s1, s2;
string in;
stringstream ss;

cout << "Enter complex equation ..." << endl;
cout << " (a +|- bi) op (c +|- di) " << endl;
cout << "where op is one of : " << ops << endl;
while (true) {
cout << endl << "> ";
getline(cin,in);
ss.clear(); ss.str(in);a;
if ( (ss >> lp >> a >> signChar >> b >> i >> rp >> opChar) &&
(lp == openParen) && (i == iChar) && (rp == closeParen) &&
( (s1 = signs.find(signChar) ) != string::npos) &&
( (op = ops.find(opChar) ) != string::npos) &&
(ss >> lp >> c >> signChar >> d >> i >> rp) &&
( (s2 = signs.find(signChar) ) != string::npos) &&
(lp == openParen) && (i == iChar) && (rp == closeParen) ) {

b *= negPos[s1]; d *= negPos[s2];
c1 = new complex<float>(a,b);
c2 = new complex<float>(c,d);
switch (opChar) {
case '+' : result = *c1 + *c2; break;
case '-' : result = *c1 - *c2; break;
case '*' : result = *c1 * *c2; break;
case '/' : result = *c1 / *c2; break;
}
cout << endl << in << " = (" << noshowpos << result.real()
<< showpos << result.imag() << "i)" << endl;
delete c1;
delete c2;
}
}
return 0;
}

lesca · 11-10-2010, 04:28 AM

Sorry, I just have misunderstand your question ...

But I would like to give you some docs about operator overloading:

http://www.parashift.com/c++-faq-lit...html#faq-13.10

Hope that would help you.

x-nc · 11-10-2010, 05:12 AM

I couldn't quite follow the code in the original post so I did a little formatting and used the code block tags to make it a bit easier to read. FWLIW, when I try this out it just goes into an infinite loop on the input. But my C++ skills are nascent at best.

Code:

#include <iostream>
#include <iomanip>
#include <string>
#include <sstream>
#include <complex>

using namespace std;

const char openParen = '(';
const char closeParen = ')';
const char iChar = 'i';
const string ops("+-*/");
const string signs("-+");
const int negPos[] = { -1, 1 };

int main(int argc, char *argv[]) {

    complex<float> *c1, *c2, result;
    float a, b, c, d;
    char opChar, lp, rp, signChar, i;
    size_t op, s1, s2;
    string in;
    stringstream ss;

    cout << "Enter complex equation ..." << endl;
    cout << " (a +|- bi) op (c +|- di) " << endl;
    cout << "where op is one of : " << ops << endl;
	
    while (true) {
        cout << endl << "> ";
        getline(cin,in);
        ss.clear(); ss.str(in);a;
	
        if ( (ss >> lp >> a >> signChar >> b >> i >> rp >> opChar) &&
           (lp == openParen) && (i == iChar) && (rp == closeParen) &&
           ( (s1 = signs.find(signChar) ) != string::npos) &&
           ( (op = ops.find(opChar) ) != string::npos) &&
           (ss >> lp >> c >> signChar >> d >> i >> rp) &&
           ( (s2 = signs.find(signChar) ) != string::npos) &&
           (lp == openParen) && (i == iChar) && (rp == closeParen) ) {

           b *= negPos[s1]; d *= negPos[s2];
           c1 = new complex<float>(a,b);
           c2 = new complex<float>(c,d);

           switch (opChar) {
               case '+' : result = *c1 + *c2; break;
               case '-' : result = *c1 - *c2; break;
               case '*' : result = *c1 * *c2; break;
               case '/' : result = *c1 / *c2; break;
           }

           cout << endl << in << " = (" << noshowpos << result.real()
                << showpos << result.imag() << "i)" << endl;

           delete c1;
           delete c2;
        }
    }
    return 0;
}