initial commit

.gitignore

@@ -0,0 +1,6 @@
+add
+div
+mean
+mul
+sub
+sum

add.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#ifndef eprintf
+#define eprintf(...) fprintf(stderr, __VA_ARGS__)
+#endif
+
+int main(int argc, char **argv) {
+  int v1;
+  int v2;
+  int out;
+  int e1;
+  int e2;
+
+  e1 = sscanf(argv[1], "%i", &v1);
+  e2 = sscanf(argv[2], "%i", &v2);
+  if(e1==EOF) {
+    eprintf("%s: argument %d cannot be parsed as int", *argv);
+    return 1;
+  } else if(e2==EOF) {
+        eprintf("%s: argument %d cannot be parsed as int", *argv);
+    return 1;
+  }
+  out=v1+v2;
+  printf("%d\n",out);
+  return 0;
+}

div.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#ifndef eprintf
+#define eprintf(...) fprintf(stderr, __VA_ARGS__)
+#endif
+
+int main(int argc, char **argv) {
+  int v1;
+  int v2;
+  int out;
+  int e1;
+  int e2;
+
+  e1 = sscanf(argv[1], "%i", &v1);
+  e2 = sscanf(argv[2], "%i", &v2);
+  if(e1==EOF) {
+    eprintf("%s: argument %d cannot be parsed as int", *argv);
+    return 1;
+  } else if(e2==EOF) {
+        eprintf("%s: argument %d cannot be parsed as int", *argv);
+    return 1;
+  }
+  out=v1/v2;
+  printf("%d\n",out);
+  return 0;
+}

mean.c

@@ -0,0 +1,18 @@
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+  int buf;
+  int acc;
+  int err;
+  for(int i=1;i<argc;i++) {
+    err=sscanf(argv[i], "%i", &buf);
+    if(err!=1) {
+      fprintf(stderr, "%s: arg #%d not an integer.\n",*argv,i);
+      return 1;
+    }
+    acc+=buf;
+  }
+  acc/=argc-1;
+  printf("%d\n",acc);
+  return 0;
+}

mul.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#ifndef eprintf
+#define eprintf(...) fprintf(stderr, __VA_ARGS__)
+#endif
+
+int main(int argc, char **argv) {
+  int v1;
+  int v2;
+  int out;
+  int e1;
+  int e2;
+
+  e1 = sscanf(argv[1], "%i", &v1);
+  e2 = sscanf(argv[2], "%i", &v2);
+  if(e1==EOF) {
+    eprintf("%s: argument %d cannot be parsed as int", *argv);
+    return 1;
+  } else if(e2==EOF) {
+        eprintf("%s: argument %d cannot be parsed as int", *argv);
+    return 1;
+  }
+  out=v1*v2;
+  printf("%d\n",out);
+  return 0;
+}

sub.c

@@ -0,0 +1,25 @@
+#include <stdio.h>
+#ifndef eprintf
+#define eprintf(...) fprintf(stderr, __VA_ARGS__)
+#endif
+
+int main(int argc, char **argv) {
+  int v1;
+  int v2;
+  int out;
+  int e1;
+  int e2;
+
+  e1 = sscanf(argv[1], "%i", &v1);
+  e2 = sscanf(argv[2], "%i", &v2);
+  if(e1==EOF) {
+    eprintf("%s: argument %d cannot be parsed as int", *argv);
+    return 1;
+  } else if(e2==EOF) {
+        eprintf("%s: argument %d cannot be parsed as int", *argv);
+    return 1;
+  }
+  out=v1-v2;
+  printf("%d\n",out);
+  return 0;
+}

sum.c

@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+int main(int argc, char **argv) {
+  int buf;
+  int acc;
+  int err;
+  for(int i=1;i<argc;i++) {
+    err=sscanf(argv[i], "%i", &buf);
+    if(err!=1) {
+      fprintf(stderr, "sscanf error: not an integer.\n");
+      return 1;
+    }
+    acc+=buf;
+  }
+  printf("%d\n",acc);
+  return 0;
+}