From ffb35f129d327a5f09ae06c048c5af4142148682 Mon Sep 17 00:00:00 2001
From: Maryna Kravtsova <maryna.kravtsova@student.tuke.sk>
Date: Sat, 24 Oct 2020 16:50:10 +0000
Subject: [PATCH] Update 'a2/program.c'

---
 a2/program.c | 55 ++++++++++++++++++++++++++++++++++------------------
 1 file changed, 36 insertions(+), 19 deletions(-)

diff --git a/a2/program.c b/a2/program.c
index a7e2c41..c44595b 100644
--- a/a2/program.c
+++ b/a2/program.c
@@ -9,6 +9,8 @@ struct stack{
     int size;
 }stack;
 
+///add bracket to stack
+
 void push(char ch){
     if(stack.size < 100){
         stack.size++;
@@ -16,7 +18,9 @@ void push(char ch){
     }
     else
         exit(0);
-} 
+}
+
+///if i have opening bracket in stack, then decrement size
 
 void pop(){
     if(stack.size >= 0)
@@ -25,6 +29,8 @@ void pop(){
         exit(0);
 }
 
+///compare brackets
+
 bool find_pair(char a, char b){
     if(a == '(' && b == ')') 
         return true;
@@ -36,8 +42,10 @@ bool find_pair(char a, char b){
         return true;
 
     return false;
-
 }
+
+///function to find right pair
+
 char right_pair(char a){
     char b;
     if(a == '(')
@@ -52,6 +60,8 @@ char right_pair(char a){
     return b;    
 }
 
+///find the last opening bracket in the stack
+
 char gettop(){
     return stack.data[stack.size];
 }
@@ -68,53 +78,60 @@ int main(){
 
     int l = strlen(line);
     int i, j = -1, f = -1;;
-    char *l_bracket = calloc(l, sizeof(char));
-    char *r_bracket = calloc(l, sizeof(char));
+    char *o_bracket = calloc(l, sizeof(char));
+    char *c_bracket = calloc(l, sizeof(char));
      
     for(i = 0; i < l; i++){
         if(line[i] == '{' || line[i] == '(' || line[i] == '[' || line[i] == '<'){
             push(line[i]);
             j++;
             f++;
-            l_bracket[j] = gettop();
-            r_bracket[f] = right_pair(l_bracket[j]);
+            o_bracket[j] = gettop();                   //get opening bracket from the stack
+            c_bracket[f] = right_pair(o_bracket[j]);   //get closing bracket 
         }
-        if(line[i] == '}' || line[i] == ')' || line[i] == ']' || line[i] == '>'){   
-            if(stack.size == -1){
+        if(line[i] == '}' || line[i] == ')' || line[i] == ']' || line[i] == '>'){
+
+            if(stack.size == -1){                      //if there is no opening bracket in the stack
                 printf("Unexpected closing bracket %c in %d\n", line[i], i);
                 return 0; 
 
             }
-            else if(!find_pair(gettop(), line[i])){
-                printf("Crossed bracket %c in %d, expected %c \n", line[i], i, r_bracket[f]);
+            else if(!find_pair(gettop(), line[i])){    //if there is another closing bracket 
+                printf("Crossed bracket %c in %d, expected %c \n", line[i], i, c_bracket[f]);
                 return 0;            
             }
             else{
-                 r_bracket[f] = 0;
-                 f--;
+                 c_bracket[f] = 0;                     //if closing bracket is correct then reducee array
+                 f--;                                  //if i didn't find a correct bracket, then keep it in the array
                  pop();
             }
         }
     }
    
     int begin = 0;
-    int end = strlen(r_bracket);
+    int end = strlen(c_bracket);
     int temp;
+
+    //now i have all missing closing brackets in array
+ 
+    //flip array
     while(begin < end){
-        temp = r_bracket[begin];
-        r_bracket[begin++] = r_bracket[--end];
-        r_bracket[end] = temp;
+        temp = c_bracket[begin];
+        c_bracket[begin++] = c_bracket[--end];
+        c_bracket[end] = temp;
     }
 
+    //if program pop all opening brackets from the stack, then stack size must be -1;
     if(stack.size == -1){
         printf("All brackets OK\n");
     }
+    //if no, then program didn't find closing bracket
     else {
-        printf("Missing closing brackets: %s\n", r_bracket);        
+        printf("Missing closing brackets: %s\n", c_bracket);        
     }
 
-    free(l_bracket);
-    free(r_bracket);
+    free(o_bracket);
+    free(c_bracket);
     
     return 0;
 }