Create clean version for 01scanner, only tree files , Removed useless symbols.

01_Scanner/cleancode/README.md

@@ -0,0 +1,3 @@
+# I make a clean version for learning.(only tree file)
+`if require: chmod +x run.sh`
+run it:  ./run.sh

01_Scanner/cleancode/const.h

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+#pragma once
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+extern int Line;
+extern int Putback;
+extern FILE* Infile;
+
+typedef struct token{
+    int type_idx;
+    int value;
+}Token;
+
+enum {
+  T_PLUS, T_MINUS, T_STAR, T_SLASH, T_INTLIT
+};
+
+extern int scan(Token*);
+
+static char const * const token_str[] = { "+", "-", "*", "/", "intlit" };

01_Scanner/cleancode/data

@@ -0,0 +1 @@
+1 + 3 * 5 /2 

01_Scanner/cleancode/main.c

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+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "const.h"
+
+int Line = 0;
+int Putback = '\n';
+FILE *Infile = NULL;
+
+static void scanfile()
+{
+    Token t;
+    while (scan(&t))
+    {
+        printf("token: %s", token_str[t.type_idx]);
+        if (t.type_idx == T_INTLIT)
+            printf(",value: %d", t.value);
+        putchar('\n');
+    }
+}
+int main(int argc, char *argv[])
+{
+    if (argc != 2){
+        puts("usage:scanner input.txt");
+        exit(0);
+    }
+    Infile = fopen(argv[1], "r");
+    printf("opend file: %s\n",argv[1]);
+    if(Infile == NULL){
+        puts("file not open!");
+    }
+    scanfile();
+    return 0;
+}

01_Scanner/cleancode/run.sh

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+#!/bin/bash 
+
+gcc main.c scan.c -o scanner
+./scanner data

01_Scanner/cleancode/scan.c

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+#include "const.h"
+#include <ctype.h>
+static int chrpos(char *s, int c)
+{
+    char *p;
+
+    p = strchr(s, c);
+    return (p ? p - s : -1);
+}
+static void putback(int c)
+{
+    Putback = c;
+}
+
+static int next()
+{
+    int c;
+    if (Putback)
+    {
+        c = Putback;
+        Putback = 0;
+        return c;
+    }
+    c = fgetc(Infile);
+    if (c == '\n')
+        Line++;
+    return c;
+}
+static int scanint(int c)
+{
+    int k, val = 0;
+
+    while ((k = chrpos("0123456789", c)) >= 0)
+    {
+        val = val * 10 + k;
+        c = next();
+    }
+
+    putback(c);
+    return val;
+}
+
+static int skip(void)
+{
+    int c;
+
+    c = next();
+    while (' ' == c || '\t' == c || '\n' == c || '\r' == c || '\f' == c)
+    {
+        c = next();
+    }
+    return (c);
+}
+
+int scan(Token *t)
+{
+    int c = skip();
+    // printf("read char: %c\n", c);
+    switch (c)
+    {
+    case EOF:
+        return (0);
+    case '+':
+        t->type_idx = T_PLUS;
+        break;
+    case '-':
+        t->type_idx = T_MINUS;
+        break;
+    case '*':
+        t->type_idx = T_STAR;
+        break;
+    case '/':
+        t->type_idx = T_SLASH;
+        break;
+    default:
+        if (isdigit(c))
+        {
+            t->type_idx = T_INTLIT;
+            t->value = scanint(c);
+            break;
+        }
+        printf("Unrecognised character %c on line %d\n", c, Line);
+        exit(1);
+    }
+
+    return 1;
+}