From 903ff13b3be1c29e35621afcef116329e2da16c8 Mon Sep 17 00:00:00 2001
From: Vicente <vicente@masba.net>
Date: Tue, 2 Apr 2024 21:15:25 -0300
Subject: Implemented left recursion descent parser

---
 .gitignore |  1 +
 Makefile   |  2 +-
 main.c     |  9 ++++++---
 tree.c     | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tree.h     | 18 +++++++++---------
 5 files changed, 77 insertions(+), 13 deletions(-)
 create mode 100644 tree.c

diff --git a/.gitignore b/.gitignore
index e660fd9..e86b018 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 bin/
+a.out
diff --git a/Makefile b/Makefile
index 2e857bc..98af738 100644
--- a/Makefile
+++ b/Makefile
@@ -12,7 +12,7 @@ EXES    := $(ARCFIND)
 CFLAGS  := $(addprefix -I,$(SRCDIRS)) $(XTRAFLAGS)
 LDLIBS  :=
 
-ARCFIND_O  := $(addprefix ./bin/, main.o)
+ARCFIND_O  := $(addprefix ./bin/, main.o, tree.o)
 
 all: $(EXES)
 .PHONY: all
diff --git a/main.c b/main.c
index bfea3b3..566330c 100644
--- a/main.c
+++ b/main.c
@@ -1,6 +1,9 @@
 #include <stdio.h>
+#include "tree.h"
 
-int main(void) {
-  printf("arcfind!\n");
-  return 0;
+int main(){
+  char str[100];
+  printf("type in your tree(no spaces please): ");
+  scanf("%[^\n]", str);
+  printTree(parse(str),0);
 }
diff --git a/tree.c b/tree.c
new file mode 100644
index 0000000..e5fc435
--- /dev/null
+++ b/tree.c
@@ -0,0 +1,60 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "tree.h"
+
+int strichar(const char *str, char c){
+  for(int i=0; str[i]!='\0';i++){
+    if(str[i] == c) return i;
+  }
+  return -1; //char not found
+}
+const char ops[] = {'+','*','!'}; //ordem inversa
+const int opsize = sizeof(ops)/sizeof(char);
+node * parse(char *str) { //expects a string with no whitespace
+
+  int j,i;
+  for(i=0; i<opsize; i++){
+    j=strichar(str,ops[i]);
+    if(j>=0) break;
+  }
+
+  node *this = (node *)malloc(sizeof(node));
+
+  if(j<0) {
+    this->type = LTTR;
+    this->el = str[0];
+  }
+
+  else{
+    this->el = ops[i];
+    if(i==2) {
+      this->type = UNOP;
+      this->child[0] = parse(str+j+1);
+    }
+    else {
+      str[j] = '\0';
+      this->type = BIOP;
+      this->child[0] = parse(str);
+      this->child[1] = parse(str+j+1);
+    }
+  }
+  return this;
+}
+
+void printTree(node *root, int level) {
+  if (root == NULL)
+    return;
+
+  if (level) {
+    for (int i = 1; i < level; i++) {
+      printf("│  ");
+    }
+    printf("├─ ");
+  }
+  printf("%c\n", root->el);
+  for (int i = 0; i < 2; i++) {
+    if (root->child[i] != NULL) {
+      printTree(root->child[i], level + 1);
+    }
+  }
+}
diff --git a/tree.h b/tree.h
index cf4d825..a58d270 100644
--- a/tree.h
+++ b/tree.h
@@ -1,13 +1,13 @@
 enum nodeType {
-	BIOP,
-	UNOP,
-	LTTR
+  BIOP,
+  UNOP,
+  LTTR
 };
 
-typedef struct {
-	enum nodeType type;
-	char el;
-	struct node *child[2];
+typedef struct node {
+  enum nodeType type;
+  char el;
+  struct node *child[2];
 } node;
-
-node* parse(const char *str);
+node * parse(char *str);
+void printTree(node *root, int level);
-- 
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