upload 4.11

.vs/CMakeWorkspaceSettings.json

@@ -0,0 +1,3 @@
+{
+  "enableCMake": true
+}

.vs/launch.vs.json

@@ -0,0 +1,12 @@
+{
+  "version": "0.2.1",
+  "defaults": {},
+  "configurations": [
+    {
+      "type": "default",
+      "project": "CMakeLists.txt",
+      "projectTarget": "C_primer.exe",
+      "name": "C_primer.exe"
+    }
+  ]
+}

1/main.c

@@ -1,6 +1,8 @@
 #include <stdio.h>
 
-int main() {
+int main(void) 
+{
     printf("Hello, World!\n");
+
     return 0;
 }

13/13.1.c

@@ -4,7 +4,7 @@ int main (int argc, char * argv[])
 {
 	int ch;
 	FILE * fp;
-	unsigned long count =0;
+	unsigned long count = 0;
 
 	if (argc != 2)
 	{

13/13.1.c~

@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <stdlib.h>
+int main (int argc, char * argv[])
+{
+	int ch;
+	FILE * fp;
+	unsigned long count =0;
+
+	if (argc != 2)
+	{
+		printf ("usage: %s filename\n", argv[0]);
+		exit (EXIT_FAILURE);
+	}
+	else;
+
+	if (!(fp = fopen(argv[1], "r")))
+	{
+		printf ("can't open %s\n", argv[1]);
+		exit (EXIT_FAILURE);
+	}
+	else;
+
+	while ((ch = getc(fp)) != EOF)
+	{
+		putc (ch, stdout);
+		count ++;
+	}
+
+	if (fclose(fp))
+	{
+		printf("error in closing file %s\n", argv[1]);
+	}
+	else;
+
+	printf ("file %s has %lu characters\n", argv[1], count);
+
+	return 0;
+}

13/13.10.c

@@ -0,0 +1,18 @@
+#include <stdio.h>
+#include <stdlib.h>
+int main(void)
+{
+  FILE* fp;
+  int k;
+
+  fp = fopen("test1310", "w+");
+
+  for (k = 0; k < 30; k++)
+  {
+    fputs("Nanette eats geldtin. \n", fp);
+  }
+
+  fclose(fp);
+
+  return 0;
+}

13/13.11.c

@@ -0,0 +1,45 @@
+#include <stdio.h>
+#include <stdlib.h>
+int main(int argc, char* argv[]) {
+  FILE* fp;
+  double ret = 0, num;
+  int cot = 0;
+
+  if (argc == 2) 
+  {
+    if ((fp = fopen(argv[1], "r")) == NULL) 
+    {
+      printf("wrong in opening %s. \n", argv[1]);
+      exit(EXIT_FAILURE);
+    }
+  }
+  else if (argc == 1) 
+  {
+    fp = stdin;
+    printf("please enter numbers, q to quit: \n");
+  }
+  else 
+  {
+    printf("fullstop. \n");
+    exit(EXIT_FAILURE);
+  }
+
+  while (fscanf(fp, "%lf", &num) == 1) 
+  {
+    ret += num;
+    cot++;
+  }
+
+  if (cot != 0) 
+  {
+    ret /= cot;
+    printf("%lf\n", ret);
+  }
+  else 
+  {
+    printf("No numbers read.\n");
+  }
+
+  fclose(fp);
+  return 0;
+}

13/13.12.c

@@ -0,0 +1,76 @@
+#include <stdio.h>
+#include <stdlib.h>
+int main(int argc, char * argv[])
+{
+  char ch, buf[256];
+  FILE* fp1;
+
+  if (argc < 3)
+  {
+    printf("handle failure. \n");
+    exit(EXIT_FAILURE);
+  }
+  else;
+
+  if ((fp1 = fopen(argv[2], "r")) == NULL)
+  {
+    printf("open %s failure. \n", argv[2]);
+    exit(EXIT_FAILURE);
+  }
+  else;
+
+  ch = argv[1][0];
+  setvbuf(fp1, buf, _IOLBF, sizeof(buf));
+
+  while (fgets(buf, 256, fp1))
+  {
+    for (int i = 0; buf[i] != '\0'; i ++)
+    {
+      if (buf[i] == ch)
+      {
+        fputs(buf, stdout);
+        break;
+      }
+    }
+  }
+
+  fclose(fp1);
+  return 0;
+}
+
+/*
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char* argv[]) {
+  char ch, buf[256];
+  FILE* fp1;
+
+  if (argc < 3) {
+    printf("Usage: %s filename character\n", argv[0]);
+    exit(EXIT_FAILURE);
+  }
+
+  fp1 = fopen(argv[2], "r");
+  if (fp1 == NULL) {
+    printf("Failed to open %s\n", argv[1]);
+    exit(EXIT_FAILURE);
+  }
+
+  ch = argv[1][0];
+
+  setvbuf(fp1, buf, _IOLBF, sizeof(buf));
+
+  while (fgets(buf, sizeof(buf), fp1)) {
+    for (int i = 0; buf[i] != '\n'; i++) {
+      if (buf[i] == ch) {
+        fputs(buf, stdout);
+        break;
+      }
+    }
+  }
+
+  fclose(fp1);
+  return 0;
+}
+*/

13/13.13.c

@@ -0,0 +1,35 @@
+#include <stdio.h>
+#include <stdlib.h>
+int main (void)
+{
+  int ch;
+  FILE * fp;
+  unsigned long count = 0;
+  char str[50];
+
+  printf ("please enter file's name: \n");
+  scanf ("%s", str);
+
+  if (!(fp = fopen(str, "r")))
+  {
+    printf ("can't open %s\n", str);
+    exit (EXIT_FAILURE);
+  }
+  else;
+
+  while ((ch = getc(fp)) != EOF)
+  {
+    putc (ch, stdout);
+    count ++;
+  }
+
+  if (fclose(fp))
+  {
+    printf ("error in closing file %s\n", str);
+  }
+  else;
+
+  printf ("file %s has %lu characters\n", str, count);
+
+  return 0;
+}

13/13.14.c

@@ -0,0 +1,30 @@
+#include <stdio.h>
+#include <stdlib.h>
+int main (int argc, char * argv[])
+{
+  FILE * fp1, * fp2;
+
+  if (argc != 3)
+  {
+    printf ("negative enter. \n");
+    exit (EXIT_FAILURE);
+  }else;
+
+  if ((fp1 = fopen (argv[1], "r")) == NULL)
+  {
+    printf("error opening %s. \n", argv[1]);
+    exit(EXIT_FAILURE);
+  }else;
+
+  if ((fp2 = fopen (argv[2], "w")) == NULL)
+  {
+    printf("error opening %s. \n", argv[2]);
+    exit(EXIT_FAILURE);
+  }else;
+
+  for (char ch; (ch = getc(fp1)) != EOF; putc(ch, fp2));
+
+  fclose (fp1);
+  fclose (fp2);
+  return 0;
+}

13/13.15.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+int main (void)
+{
+  FILE * fp1, * fp2;
+  char f_name_1[50], f_name_2[50];
+
+  printf ("this program turns lower into upper. \n");
+  printf ("please enter the first file name: \n");
+  scanf ("%s", f_name_1);
+  printf ("now enter the second file name: \n");
+  scanf ("%s", f_name_2);
+
+  if ((fp1 = fopen (f_name_1, "r")) == NULL)
+  {
+    printf("error opening %s. \n", f_name_1);
+    exit(EXIT_FAILURE);
+  }else;
+
+  if ((fp2 = fopen (f_name_2, "w")) == NULL)
+  {
+    printf("error opening %s. \n", f_name_2);
+    exit(EXIT_FAILURE);
+  }else;
+
+  for (char ch; (ch = getc (fp1)) != EOF; islower (ch) ? putc (toupper (ch), fp2): putc (ch, fp2));
+
+  fclose (fp1);
+  fclose (fp2);
+  return 0;
+}