Renaming all folders

03_BufferedIO/README.md

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+# Chapter 3 – Buffered I/O
+
+## Difference Between Byte-Level and Buffered I/O
+- **System calls** like `read()` and `write()` operate at a low level: each call may result in direct disk access.
+- **C libraries** use buffered I/O (`fread()`, `fwrite()`, `fprintf()`), accumulating data in memory to reduce system calls.
+
+## Buffered I/O API
+- Uses `FILE *` type from `<stdio.h>`.
+- Functions:
+  - `fopen()`, `fclose()`: open/close file.
+  - `fread()`, `fwrite()`: binary I/O.
+  - `fprintf()`, `fscanf()`, `fgets()`, `fputs()`: formatted or text I/O.
+
+## Types of Buffering
+- **Fully buffered**: flush when buffer is full.
+- **Line buffered**: flush at end of line (e.g., terminals).
+- **Unbuffered**: no accumulation (e.g., stderr).
+
+## Buffer Management
+- `setvbuf()` or `setbuf()` allows custom buffering.
+- Useful for optimizing performance or interactive environments.
+
+## When to Use Buffered I/O
+- When performance matters and immediate file system synchronization isn't required.
+- For formatted I/O, the C library offers more simplicity and readability.
+

03_BufferedIO/binarydata.c

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+/*
+ * SPDX-License-Identifier: MIT
+ * Copyright (c) 2025 Fabio Scotto di Santolo
+ */
+
+
+#include <stdio.h>
+
+int main(void)
+{
+	FILE *in, *out;
+	struct pirate {
+		char name[100];		/* real name */
+		unsigned long booty;	/* in pounds sterling */
+		unsigned int beard_len; /* in inches */
+	} p, blackbeard = {"Edward Teach", 950, 48};
+
+	out = fopen("data", "w");
+	if (!out) {
+		perror("fopen");
+		return 1;
+	}
+	if (!fwrite(&blackbeard, sizeof(struct pirate), 1, out)) {
+		perror("fwrite");
+		return 1;
+	}
+	if (fclose(out)) {
+		perror("fclose");
+		return 1;
+	}
+
+	in = fopen("data", "r");
+	if (!in) {
+		perror("fopen");
+		return 1;
+	}
+	if (!fread(&p, sizeof(struct pirate), 1, in)) {
+		perror("fread");
+		return 1;
+	}
+	if (fclose(in)) {
+		perror("fclose");
+		return 1;
+	}
+	printf("name=\"%s\" booty=%lu beard_len=%u\n", p.name, p.booty,
+	       p.beard_len);
+	return 0;
+}

03_BufferedIO/input.c

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+/*
+ * SPDX-License-Identifier: MIT
+ * Copyright (c) 2025 Fabio Scotto di Santolo
+ */
+
+
+#include <limits.h>
+#include <stdio.h>
+
+int main(void)
+{
+	printf("Limit buffer size is %u bytes.\n", LINE_MAX);
+	printf("Buffer size is %u bytes.\n", BUFSIZ);
+}