The Discrete Cosine Transform: DCT-2D

DCT-2D.cpp

#include <iostream>
#include <fstream>
#include <math.h>

using namespace std;

#define LEN 8
#define PI 3.141592654

const char *FILEPATH = "document.txt";
double f[LEN][LEN];
double F[LEN][LEN];
double c = 1 / sqrt(2);

bool input(double arr[][LEN]);
void output(double arr[][LEN]);
void DCT();
double FDCT(int u, int v);

int main() {
    bool check = input(f);
    if(!check) {
        return -1;
    }
    cout << "\nInput array:" << endl;
    output(f);

    DCT();

    cout << "\nOutput array:" << endl;
    output(F);

    return 0;
}

bool input(double arr[][LEN]) {
    int choose;
    cout << "+---------------- DCT ----------------+" << endl;
    cout << "|                                     |" << endl;
    cout << "|    1. Input file                    |" << endl;
    cout << "|    2. Input keyboard                |" << endl;
    cout << "|                                     |" << endl;
    cout << "+-------------------------------------+" << endl;
    cout << "Choose: ";
    cin >> choose;

    if (choose == 1) {
        ifstream fileInput(FILEPATH);
        if (fileInput.fail()) {
            cout << "Failed to open file!" << endl;
            return false;
        }
        for (int j = 0; j < LEN; ++j) {
            for (int k = 0; k < LEN; ++k) {
                fileInput >> arr[j][k];
            }
        }
        fileInput.close();
    } else if(choose == 2) {
        for (int j = 0; j < LEN; ++j) {
            for (int k = 0; k < LEN; ++k) {
                cout << "f[" << j << "][" << k << "] = ";
                cin >> arr[j][k];
            }
        }
    } else {
        cout << "\nSyntax error !" << endl;
        return false;
    }
    return true;
}

void output(double arr[][LEN]) {
    for (int j = 0; j < LEN; ++j) {
        for (int k = 0; k < LEN; ++k) {
            cout << (int)round(arr[j][k]) << "\t";
        }
        cout << endl;
    }
}

void DCT() {
    for (int j = 0; j < LEN; ++j) {
        for (int k = 0; k < LEN; ++k) {
            F[j][k] = FDCT(j, k);
        }
    }
}

double FDCT(int u, int v) {
    double Cu = (u == 0) ? c : 1.0;
    double Cv = (v == 0) ? c : 1.0;
    double sol = (Cu * Cv) / 4;
    double sum = 0.0;
    int _j;

    for (int j = 0; j < LEN; ++j) {
        _j = j << 1;
        for (int k = 0; k < LEN; ++k) {
            sum += f[j][k] * cos(((_j + 1) * u * PI)/ 16) * cos(((k << 1 + 1) * v * PI)/ 16);
        }
    }
    return sol * sum;
}

document.txt

98	92	95	80	75	82	68	50
97	91	94	79	74	81	67	49
95	89	92	77	72	79	65	47
93	87	90	75	70	77	63	45
91	85	88	73	68	75	61	43
89	83	86	71	66	73	59	41
87	81	84	69	64	71	57	39
85	79	82	67	62	69	55	37