First working version of ch26 ex25

ex25.c

@@ -0,0 +1,135 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include "dbg.h"
+
+#define MAX_DATA 100
+
+
+int read_string(char **out_string, int max_buffer)
+{
+    *out_string = calloc(1, max_buffer + 1);
+    check_mem(*out_string);
+
+    char *result = fgets(*out_string, max_buffer, stdin);
+    check(result != NULL, "Input error.");
+
+    return 0;
+
+error:
+    if(*out_string) free(*out_string);
+    *out_string = NULL;
+    return -1;
+}
+
+
+int read_int(int *out_int)
+{
+    char *input = NULL;
+    int rc = read_string(&input, MAX_DATA);
+    check(rc == 0, "Failed to read number.");
+
+    *out_int = atoi(input);
+
+    free(input);
+    return 0;
+
+error:
+    if(input) free(input);
+    return -1;
+}
+
+
+int read_scan(const char *fmt, ...)
+{
+    int i = 0;
+    int rc = 0;
+    int *out_int = NULL;
+    char *out_char = NULL;
+    char **out_string = NULL;
+    int max_buffer = 0;
+
+    va_list argp;
+    va_start(argp, fmt);
+
+    for(i = 0; fmt[i] != '\0'; i++) {
+        if(fmt[i] == '%') {
+            i++;
+            switch(fmt[i]) {
+                case '\0':
+                    sentinel("Invalid format, you ended with %%.");
+                    break;
+
+                case 'd':
+                    out_int = va_arg(argp, int *);
+                    rc = read_int(out_int);
+                    check(rc == 0, "Failed to read int.");
+                    break;
+
+                case 'c':
+                    out_char = va_arg(argp, char *);
+                    *out_char = fgetc(stdin);
+                    break;
+
+                case 's':
+                    max_buffer = va_arg(argp, int);
+                    out_string = va_arg(argp, char**);
+                    rc = read_string(out_string, max_buffer);
+                    check(rc == 0, "Failed to read string.");
+                    break;
+
+                default:
+                    sentinel("Invalid format.");
+            }
+        } else {
+            fgetc(stdin);
+        }
+
+        check(!feof(stdin) && !ferror(stdin), "Input error.");
+    }
+
+    va_end(argp);
+    return 0;
+
+error:
+    va_end(argp);
+    return -1;
+}
+
+
+int main(int argc, char *argv[])
+{
+    char *first_name = NULL;
+    char initial = ' ';
+    char *last_name = NULL;
+    int age = 0;
+
+    printf("What's your first name? ");
+    int rc = read_scan("%s", MAX_DATA, &first_name);
+    check(rc == 0, "Failed first name.");
+
+    printf("What's your initial? ");
+    rc = read_scan("%c\n", &initial);
+    check(rc == 0, "Failed initial.");
+
+    printf("What's your last name? ");
+    rc = read_scan("%s", MAX_DATA, &last_name);
+    check(rc == 0, "Failed last name.");
+
+    printf("How old are you? ");
+    rc = read_scan("%d", &age);
+    check(rc == 0, "Failed age.");
+
+    printf("---- RESULTS ----\n");
+    printf("First Name: %s", first_name);
+    printf("Initial: '%c'\n", initial);
+    printf("Last Name: %s", last_name);
+    printf("Age: %d\n", age);
+
+    free(first_name);
+    free(last_name);
+    return 0;
+
+error:
+    return -1;
+}