7.1 -> 7.3

Author: Gurjaka

src/chapter-7:input-output/7.1-standard-input-output/arbitrary_in_out.c renamed to src/chapter-7:input-output/7.2-formatted-output-printf/arbitrary_in_out.c

@@ -0,0 +1,66 @@
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/* minprintf: minimal printf with field width and precision */
+void minprintf(char* fmt, ...)
+{
+    va_list ap;
+    char *p, *sval;
+    int ival;
+    double dval;
+
+    va_start(ap, fmt);
+    for (p = fmt; *p; p++)
+    {
+        if (*p != '%')
+        {
+            putchar(*p);
+            continue;
+        }
+
+        // Start parsing format
+        p++; // skip '%'
+
+        // Parse optional width and precision
+        char format[32] = "%";
+        int i = 1;
+
+        while (isdigit(*p) || *p == '.' || *p == '-')
+        {
+            if (i < sizeof(format) - 1)
+                format[i++] = *p++;
+        }
+
+        format[i++] = *p; // type specifier like d, f, s
+        format[i] = '\0';
+
+        switch (*p)
+        {
+            case 'd':
+                ival = va_arg(ap, int);
+                printf(format, ival);
+                break;
+            case 'f':
+                dval = va_arg(ap, double);
+                printf(format, dval);
+                break;
+            case 's':
+                sval = va_arg(ap, char*);
+                printf(format, sval);
+                break;
+            default:
+                // Unrecognized specifier
+                putchar(*p);
+                break;
+        }
+    }
+    va_end(ap);
+}
+
+int main(void)
+{
+    minprintf("%.5d", 123);
+    return EXIT_SUCCESS;
+}

src/chapter-7:input-output/7.3-variable-length-argument-lists/minprintf.c

@@ -1,22 +1,23 @@
 
-# Exercise 7-3
+## Exercise 7-3 — The C Programming Language, 2nd Edition
 
-## Task
+Revise the `minprintf` function from Chapter 7 to support more of the formatting capabilities of the standard `printf` function. The original `minprintf` handles only a limited set of conversion specifiers (like `%d`, `%f`, `%s`, etc.) and minimal flag support.
 
-Revise `minprintf` to handle more of the other facilities of `printf`.
+Your task is to improve it so it can interpret and pass along additional format specifiers and flags, such as:
 
-## Objective
+- Field width and precision (e.g., `%6.2f`)
+- Left-justification (`%-d`)
+- Zero-padding (`%05d`)
+- Alternate form (`%#x`, `%#o`)
+- Signs (`%+d`, `% d`)
 
-Extend the functionality of the `minprintf` function from Chapter 7 of *The C Programming Language (K&R)* to support more format specifiers and flags, closer to the standard `printf` behavior.
+### Notes
 
-## Requirements
+- The goal is not to reimplement `printf` but to parse the format string more fully and correctly pass the format and corresponding argument to `printf`.
+- Use <stdarg.h> for handling the variable arguments, as shown in the original `minprintf`.
+- Test with a variety of format strings to ensure your implementation works correctly.
 
-- Add support for additional format specifiers such as:
-  - `%o`, `%x`, `%X`, `%u`, `%c`, `%e`, `%g`, etc.
-- Handle flags like:
-  - `-` (left justify), `+` (sign), `0` (zero-padding), `#` (alternate form), and space.
-- Optionally support field width and precision (e.g., `%10.2f`).
+### Deliverables
 
-## Notes
-
-This task is meant to deepen understanding of variadic functions, format parsing, and output formatting in C.
+- An updated `minprintf` function in C
+- Example usage that demonstrates the supported features