From fe62adf6845fe3eacfad2c4e63a675c45248ead2 Mon Sep 17 00:00:00 2001
From: Maryna Kravtsova <maryna.kravtsova@student.tuke.sk>
Date: Sat, 24 Oct 2020 16:59:41 +0000
Subject: [PATCH] Update 'cv3/program.c'

---
 cv3/program.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/cv3/program.c b/cv3/program.c
index 12e1807..73ca78b 100644
--- a/cv3/program.c
+++ b/cv3/program.c
@@ -10,6 +10,8 @@ struct stack {
     int size;
 };
 
+//push number to the stack
+
 void push(struct stack* stack,float values){
     if(stack->size < 10){
         stack->values[stack->size] = values;
@@ -22,6 +24,8 @@ void push(struct stack* stack,float values){
     }
 }
 
+//pop number from the stack
+
 float pop(struct stack *stack){
     if(stack->size > 0){
         float value = stack->values[stack->size-1];
@@ -58,9 +62,10 @@ int main() {
         float r = 0;
         float z = 0;
         
+        //if string is not empty
         if(line[1] != 0 && x != NULL){
 
-        
+            //if there is a wrong symbol
             if(!isdigit(line[0]) && line[0] != '+' && line[0] != '*' && line[0] != '/' && line[0] != '-'){
                 printf("bad input\n");
                 return 0;
@@ -70,8 +75,8 @@ int main() {
                 r = pop(&mystack) + pop(&mystack);
             }
             else if(line[0] == '-'){
-                z = pop(&mystack);
-                r = pop(&mystack) - z;
+                z = pop(&mystack);   //swap numbers(e.g input "3 4 -"
+                r = pop(&mystack) - z;            //output 3 - 4, not 4 - 3)
             }
             else if(line[0] == '*'){
                 r = pop(&mystack) * pop(&mystack);
@@ -86,13 +91,14 @@ int main() {
                     r = pop(&mystack) / z;
                 }
             }
-
-    
+            //if symbol is not operation, than it is number
+            //change string to float
             else {
                 r = strtof(line,&x);
             } 
-
+            //push result to stack
             push(&mystack,r);
+        
             print_stack(&mystack);
         }
         else{