From ee38e0e95e8d089670f07eb3da671e232242ea55 Mon Sep 17 00:00:00 2001
From: mgandy0123 <mgandy4567@gmail.com>
Date: Fri, 4 Mar 2022 15:30:49 +0800
Subject: [PATCH 1/2] =?UTF-8?q?=E5=B3=B0=E6=AF=85++?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 readme.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/readme.md b/readme.md
index 7bb099d..5e10cba 100644
--- a/readme.md
+++ b/readme.md
@@ -9,3 +9,4 @@
 3. 繼續寫下去 XD
 4. 大家來簽到吧
 5. 這是一個測試
+6. Binchiling! 峰

From 86f31987b2094f31fb1a65e35b75c093d3a9c7ca Mon Sep 17 00:00:00 2001
From: mgandy0123 <mgandy4567@gmail.com>
Date: Wed, 9 Mar 2022 22:04:23 +0800
Subject: [PATCH 2/2] Chen Feng-Yi  5_prcatice.c

finish the code
---
 5_practice.c | 44 ++++++++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/5_practice.c b/5_practice.c
index 70d6651..b69de9b 100644
--- a/5_practice.c
+++ b/5_practice.c
@@ -2,39 +2,47 @@
 #include <stdlib.h>	// for memory allocation
 #include <time.h>	// for time calculation
 #include <math.h>	// for sine and cosine functions
+
 int main() {
 	// Declare all the variables
-	int k, n, N;
+	int u ,k, n, N;
 	double *x, *yr, *yi;
 	time_t t;
 
 	// Input the number N
-	
-	
+	printf("Please input a number N = ");
+	scanf("%d", &N);
 	// Locate the memory for x, yr, yi;
-
-	// Initial setting for x, for example, x[k] = k
-	
-	
-	
-	
+	x = (double *) malloc(N*sizeof(double));
+	yr = (double *) malloc(N*sizeof(double));
+    yi = (double *) malloc(N*sizeof(double));
+    
+	// Initial setting for x, for example, x[k] = k, k=0..N-1 
+	for(k=0;k<N;++k) {
+		x[k] = k;
+	}
 	t = clock();	
+	
 	// yr[n]+i*yi[n] = sum(exp(-i 2 Pi k n / N)*x[k], k=0..N-1), n=0..N-1 
-
-
-
-
-
-
-
+	for(n=0;n<N;n++) {
+		yr[n] = 0.0;
+		yi[n] = 0.0;
+		u = 2*M_PI*n/N;
+		for(k=0;k<N;++k) {
+			yr[n] += cos(u*k)*x[k];
+			yi[n] -= sin(u*k)*x[k];
+		}
+	}
+	
 	// output the results
 	t = clock() - t;
 	printf("%d ms for discrete Fourier Transform of %d elements\n", t, N);
 
 	// free the memory located by x, yr, yi
-	
+	free(x);
+	free(yr);
+	free(yi);	
 	
 	
 	return 100;
 }
-