files for lecture 7

L07/add_v1.c

+#include <stdio.h>
+
+typedef struct vec2_s {
+    double x,y;
+} vec2;
+
+void vec2_add (vec2 a, vec2 b, vec2 c) {
+    c.x = a.x + b.x;
+    c.y = a.y + b.y;
+}
+
+int main () {
+    vec2 u = { 1.0, 2.0 };
+    vec2 v = { 2.0, 3.0 };
+    vec2 w = { 0, 0 };
+    vec2_add(u,v,w);
+    printf ("%.2f %.2f\n",w.x,w.y);
+}

L07/count_v1.c

+#include <stdio.h>
+#include <stdlib.h>
+
+int main (int argc, char* argv[]) {
+    if (argc < 2) {
+        printf ("command usage: %s %s\n",argv[0],"n");
+        return 1;
+    }
+    int n = atoi(argv[1]);
+    int num_pairs = 0;
+    for (int i=0;i<n;i++) {
+        for (int j=0;j<n;j++) {
+            if (i<j) {
+                num_pairs += 1;
+            }
+        }
+    }
+    printf ("There are %d possible pairs of %d points.\n",num_pairs,n);
+}

L07/extreme.py

+import sys
+import numpy as np
+import matplotlib.pyplot as plt
+
+# the name of the output file is a command line argument
+if (len(sys.argv) < 2):
+    print ("Command Usage : python3",sys.argv[0],"outfile")
+    exit(1)
+outfile = sys.argv[1]
+
+# read the data file
+data = np.loadtxt(sys.stdin)
+
+# plot the data
+plt.gca().set_aspect('equal')
+plt.scatter(data[:,0],data[:,1],s=10,color='black')
+
+# plot the special points (if additional command line argments present)
+for k in range(2,len(sys.argv)):
+    i = int(sys.argv[k])
+    plt.scatter (data[i,0],data[i,1],s=100,color='orange')
+
+# save the plot as an image
+plt.savefig(outfile)

L07/pairs.c

+#include <stdio.h>
+#include <stdlib.h>
+
+int main (int argc, char* argv[]) {
+    if (argc < 2) {
+        printf ("command usage: %s %s\n",argv[0],"n");
+        return 1;
+    }
+    int n = atoi(argv[1]);
+    for (int i=0;i<n-1;i++) {
+        for (int j=i+1;j<n;j++) {
+            printf ("%d %d\n",i,j);
+        }
+    }
+}

L07/points100.txt

+-0.285285 -0.249789
+0.549825 -0.44841
+0.264675 0.662557
+-0.371575 0.51916
+0.149416 0.025386
+-0.260369 -0.079527
+-0.088467 0.377545
+-0.368702 0.54827
+-0.568275 0.732792
+-0.882076 0.426153
+-0.494966 -0.419666
+0.588019 -0.542201
+-0.659639 0.521633
+0.546128 -0.458203
+-0.201864 0.90729
+-0.445202 0.510424
+-0.923883 0.213152
+-0.178604 -0.134069
+0.819752 0.46694
+-0.643817 -0.506508
+-0.28429 -0.05856
+0.053874 -0.072568
+-0.393404 0.525293
+-0.825468 0.558931
+0.98147 0.156388
+-0.212288 -0.012805
+-0.822678 -0.061019
+-0.043017 0.120938
+-0.420571 -0.443652
+0.186023 -0.923548
+0.084594 0.184044
+-0.050319 -0.571804
+-0.779859 0.26342
+-0.209462 -0.641269
+0.725177 0.487428
+-0.292593 -0.402471
+-0.49277 0.192058
+-0.139183 0.799168
+0.162535 0.156179
+0.541549 0.704283
+0.806409 0.230459
+-0.379849 0.901739
+0.472613 0.376156
+-0.487109 0.80138
+-0.715723 -0.519908
+-0.056526 -0.560174
+0.277816 -0.385239
+-0.658979 -0.596906
+0.749273 -0.315245
+-0.252612 0.112699
+0.810477 -0.099938
+0.605109 -0.659443
+-0.410374 -0.79696
+0.26155 0.377804
+0.939656 0.232053
+-0.147269 -0.848126
+-0.243183 -0.420227
+0.04209 -0.172037
+0.877444 0.083776
+-0.474773 0.587203
+0.580906 0.480285
+-0.202889 -0.927574
+-0.16257 -0.429955
+0.225387 -0.063909
+0.436523 0.526416
+-0.157312 -0.203698
+0.695396 0.146272
+-0.210177 0.923684
+0.381408 -0.647416
+0.089079 -0.331767
+0.623849 -0.624408
+-0.235582 0.930326
+-0.535296 0.149174
+-0.102852 -0.636314
+-0.639046 -0.241586
+-0.608494 -0.174415
+-0.035015 -0.219017
+-0.553866 -0.323574
+-0.283451 0.121833
+-0.433664 0.853236
+-0.831121 -0.318238
+0.202378 -0.062011
+-0.832565 0.206383
+0.603159 -0.121344
+-0.15034 -0.064065
+-0.90493 -0.303486
+-0.290074 0.260181
+0.178954 0.792372
+-0.762596 -0.456936
+0.956249 0.274787
+-0.152215 0.558616
+-0.243961 -0.687811
+-0.033381 -0.886103
+-0.147454 -0.781676
+-0.658208 0.285903
+0.273236 0.215035
+-0.22018 0.548046
+-0.102578 0.60073
+-0.860222 0.39712
+-0.063284 0.960043

L07/set_v1.c

+#include <stdio.h>
+
+typedef struct vec100k_s {
+    double x[100000];
+} vec100k;
+
+vec100k vec100k_set (vec100k a, int i, double b) {
+    a.x[i] = b;
+    return a;
+}
+
+int main () {
+    vec100k v;
+    for (int i=0;i<100000;i++) {
+        v = vec100k_set (v,i,i);
+    }
+    printf ("x[12345] = %.2f",v.x[12345]);
+}