last change of receiver part

 #include <iostream>
 #include "myMatrix.h"
 using namespace std;
-void scalarmult(int n, int m, float a, float *b, float *c){
-	int N = n*m;
-    for(int i=0;i<N;i++) c[i] = a*b[i];
+
+float dot(int N, float*C, float*D) {
+	float sum = 0.0;
+	for (int i = 0; i < N; i++) sum += C[i] * D[i];
+	return sum;
+}
+void scalarmult(int n, int m, float a, float *b, float *c) {
+	int N = n * m;
+	for (int i = 0; i<N; i++) c[i] = a * b[i];
 }
-void matrixadd(int n, int m, float *a, float *b, float *c){
-	int N = n*m;
-	for (int i = 0; i<N; i++) c[i] = a[i]+b[i];
+void matrixadd(int n, int m, float *a, float *b, float *c) {
+	int N = n * m;
+	for (int i = 0; i<N; i++) c[i] = a[i] + b[i];
 }
 // (N by K) C X (K by M) D = (N by M) E 
 void matrixmult(int N, int K, int M, float*C, float*D, float*E) {

 void scalarmult(int n, int m, float a, float *b, float *c);
 void matrixadd(int n, int m, float *a, float *b, float *c);
 void matrixmult(int N, int K, int M, float*C, float*D, float*E);
+float dot(int N, float*C, float*D);
 int	GaussElimination(int, float*, float*);
 void showMatrix(int n, int m, float* F);
 void showMatrix(char*name, int n, int m, float* F);

 #include "receiver.h"
-
-Creceiver::Creceiver() {}
-
-void Creceiver::demodulate() {
-
-	T = Nsamplespersymbol;
-	float c0[Nsamplespersymbol], c1[Nsamplespersymbol];
-	for (int i = 1; i <= Nsamplespersymbol; i++) {
-		c0[i - 1] = sqrt(2 / T) * cos(2 * PI / T * i);
-		c1[i - 1] = sqrt(2 / T) * sin(2 * PI / T * i);
-	}
-	float temp0[1], temp1[1];
-	for (int i = 0; i < Nbits / 2; i++) {
-		matrixmult(1, Nsamplespersymbol, 1, r + (Nbitspersymbol * i), c0, temp0);
-		matrixmult(1, Nsamplespersymbol, 1, r + (Nbitspersymbol * i), c1, temp1);
-		constellation[2 * i] = temp0[0];
-		constellation[2 * i + 1] = temp1[0];
+#include "myMatrix.h"
+Creceiver::Creceiver() {
+	float t = 0.0, T = 0.01;
+	float dt = T / Nsamplespersymbol;
+	c0t = new float[Nsamplespersymbol];
+	c1t = new float[Nsamplespersymbol];
+	for (int i = 0; i < Nsamplespersymbol; i++, t += dt) {
+		c0t[i] = cos(2.*3.141592*t / T);
+		c1t[i] = sin(2.*3.141592*t / T);
 	}
-	for (int j = 0; j < Nbits; j++) {
-		if (constellation[j] >= 0) DecodedData[j] = '0';
-		else DecodedData[j] = '1';
+}
+void Creceiver::demodulate() {
+	int nn = Nsamplespersymbol / Nbitspersymbol;
+	for (int i = 0; i < Nbits; i += 2) {
+		int symbol = detectSymbol(constellation + i, r + i * nn);
+		if (symbol == 0) { DecodedData[i] = 0; DecodedData[i + 1] = 0; }
+		else if (symbol == 1) { DecodedData[i] = 1; DecodedData[i + 1] = 0; }
+		else if (symbol == 2) { DecodedData[i] = 1; DecodedData[i + 1] = 1; }
+		else { DecodedData[i] = 0; DecodedData[i + 1] = 1; }
 	}
-
+}
+int Creceiver::detectSymbol(float *co, float* rr) {
+	float dummy[Nbitspersymbol];
+	co[0] = dot(Nsamplespersymbol, rr, c0t);
+	co[1] = dot(Nsamplespersymbol, rr, c1t);
+	if (co[0] >= 0 && co[1] >= 0)     return 0;
+	else if (co[0] < 0 && co[1] >= 0) return 1;
+	else if (co[0] < 0 && co[1] < 0)  return 2;
+	return 3;
 }
\ No newline at end of file

 #ifndef __RECEIVER
-
 #define __RECEIVER
-#define PI 3.141592
 #include <cmath>
-#include <fstream>
 #include "variables.h"
-#include "myMatrix.h"
 class Creceiver {
 public:
-	float T;
 	Creceiver();
 	float *r; // corrupted signal = received signal
 	float constellation[Nbits];
 	char DecodedData[Nbits];
 	void demodulate();
+	int detectSymbol(float *, float *);
+	float *c0t, *c1t;
 };
-
 #endif