fix: 5.1, misunderstood question

1 files changed, 42 insertions, 48 deletions

diff --git a/5.1.c b/5.1.c
index a0e0559..1301f6d 100644
--- a/5.1.c
+++ b/5.1.c
@@ -1,74 +1,68 @@
 #include <stdio.h>
 #include <ctype.h>
 
-int getint(int *np);
-char getch(void);
-void ungetch(char input);
+#define MAXBUFF 100
 
-int 
-main(void)
-{
-  int num;
+int getint(int *pn);
+int getch(void);
+void ungetch(int input);
 
-  getint(&num);
+int main(void)
+{
+        int input;
 
-  printf("%d\n", num);
+        getint(&input);
+        printf("input: %d\n", input);
 
-  return 0;
+        return 0;
 }
 
-int 
-getint(int *np)
+int getint(int *pn)
 {
-  int input, sign;
+        char input, sign;
+
+        while (isspace(input = getch()))
+                ;
 
-  /* skip space */
-  while (isspace(input = getch()))
-    ;
+        if (!isdigit(input) && input != EOF && input != '+' && input != '-') {
+                ungetch(input);
+                return 0;
+        }
 
-  if (!isdigit(input) && input != EOF && input != '+' && input != '-') {
-    ungetch(input);
-    return 0;
-  }
+        sign = (input == '-') ? -1 : 1;
 
-  sign = (input == '-') ? -1 : 1;
+        if (input == '-' || input == '+') {
+                input = getch();
 
-  if (input == '+' || input == '-')
-    while (isspace(input = getch()))
-     ;
+                if (!isdigit(input)) {
+                        ungetch((sign == -1) ? '-' : '+');
+                        return 0;
+                }
+        }
 
-  for (*np = 0; isdigit(input); input = getch())
-    *np = *np * 10 + input - '0';
+        for (*pn = 0; isdigit(input); input = getch())
+                *pn = (*pn * 10) + (input - '0');
 
-  *np *= sign;
+        *pn *= sign;
 
-  if (input != EOF)
-    ungetch(input);
+        if (input != EOF)
+                ungetch(input);
 
-  /* return last digit or EOF */
-  return input;
+        return input;
 }
 
-static char buff = -1;
+char buff[MAXBUFF];
+int bpos = 0;
 
-char 
-getch(void)
+int getch(void)
 {
-  char temp;
-
-  if (buff == -1)
-    return getchar();
-
-  temp = buff;
-  buff = -1;
-  return temp;
+        return (bpos) ? buff[--bpos] : getchar();
 }
 
-void
-ungetch(char input)
+void ungetch(int input)
 {
-  if (buff == -1)
-    buff = input;
-  else 
-    printf("Err: buffer is full\n");
+        if (bpos < MAXBUFF)
+                buff[bpos++] = input;
+        else
+                printf("err: buff full\n");
 }