i am posting the code below.... please tell me where the error is ..... i am new to codeblocks.... the error comes at swt and iswt function as undefined referrence........

#include <iostream>
#include <fstream>
#include "wavelet2d.h"
#include <vector>
#include <string>
#include <cmath>
using namespace std;

int main() {
        cout << "********J- LEVEL DISCRETE WAVELET TRANSFORM IMPLEMENTATION*********" << endl; // prints
            cout << "This program accepts signal from the user in a file format " << endl;
            cout << "and performs Discrete Wavelet Transform with specified   " << endl;
            cout << "wavelet. "                                               << endl;
            cout << "                                                             " << endl;
            cout << " The Following Wavelets are in the Database:                 " << endl;
            cout << " haar, db1, db2, db3, db4, db5, db6, db7, db8, db9, db10,  "   << endl;
            cout << " db11, db12, db13, db14, db15.                               "  << endl;
            cout << " bior1.1, bio1.3, bior1.5, bior2.2, bior2.4,bior2.6,bior2.8, " << endl;
            cout << " bior3.1, bior3.3, bior3.5, bior3.7, bior3.9, bior4.4,"        << endl;
            cout << " bior5.5, bior6.8."                                            << endl;
            cout << " coif1, coif2, coif3, coif4, coif5."                           << endl;
            cout << "Please Enter the Wavelet Name at the Prompt( No quotes)     :" << endl;

            string nm; // nm will store the name of Wavelet Family
            cin >> nm;
            cout << "Enter the name of signal file at the Prompt eg., signal.txt :" << endl;
            char inp[50];
            cin >> inp;
            vector<double> sig;
            ifstream sig_inp(inp);
        if ( !sig_inp.good()){
                cout << "The File doesn't exist"<< endl;
            while (sig_inp) {
                double temp;
                sig_inp >> temp;
            vector<double> original;
            original = sig; // Make a copy of the signal if you want to use original signal
       // later on. The other option is to use IDWT output as the SWt/ISWT system is
       // Perefect Reconstruction system.
            cout << "Please Enter the Number of DWT Stages J             :" << endl;

            int J;
            cin >> J ;

        vector<double> swt_output;

        // perform J-Level DWT
        int length;// All coefficients are of same length. Variable "length" returns length
        // of coefficients. It is not required for ISWT computations.

            swt(sig, J, nm, swt_output, length);

            ofstream swtcoeff("swtcoeff.txt");
            for (unsigned int i=0; i < swt_output.size(); i++) {
              swtcoeff << swt_output[i] << endl;
            vector<double> iswt_output;
            iswt(swt_output,J, nm,iswt_output);
            ofstream sig1("recon.txt");
            ofstream diff("diff.txt");

            cout <<" Recon signal size" << iswt_output.size() << endl;
            for (unsigned int i = 0; i < iswt_output.size(); i++){
                sig1 << iswt_output[i] << endl;
                diff << iswt_output[i] - original[i] << endl;


            return 0;

Edited 3 Years Ago by malloju

You might have to add the directory where the .h file is into the linker so it will search for it. What is the exact error yu are getting?

"Undefined reference" means the linker cannot find the actual function code. Generally, this means that you have not linked against the right library, or that you simply haven't written the code (and sometimes that you've spelled the name of a function incorrectly).

Unless the actual code of the function is in the header (which is unlikely, as that's a very, very, very bad idea) it's not a header problem. The fact that this is a linker error indicates that the compiler is happy, so I'd guess you have included the right header, containing the function prototype, but haven't linked the library.

If you're not expecting to have to write that function yourself, which I'd guess you're not, then you definitely haven't linked against the right library.

Remember, a header file is not a library.

Edited 3 Years Ago by Moschops

This article has been dead for over six months. Start a new discussion instead.