From 8c11f02f93536d098c1833c759a26d1501a84a76 Mon Sep 17 00:00:00 2001
From: Mykola Syniavskyi <mykola.syniavskyi@student.tuke.sk>
Date: Fri, 17 Oct 2025 00:20:09 +0000
Subject: [PATCH] Aktualizovat du3/program.c

---
 du3/program.c | 86 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/du3/program.c b/du3/program.c
index e69de29..7c31687 100644
--- a/du3/program.c
+++ b/du3/program.c
@@ -0,0 +1,86 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define STACK_SIZE 10
+#define BUFFER_SIZE 100
+
+struct stack {
+    float values[STACK_SIZE];
+    int size;
+};
+
+void init_stack(struct stack* s) {
+    s->size = 0;
+}
+
+int push_stack(struct stack* s, float znac) {
+    if (s->size >= STACK_SIZE) {
+        printf("stack overflow\n");
+        return 0;
+    }
+    s->values[s->size++] = znac;
+    return 1;
+}
+
+int pop_stack(struct stack* s, float* out) {
+    if (s->size < 1) {
+        printf("stack underflow\n");
+        return 0;
+    }
+    *out = s->values[--s->size]; //зменшуємо розмір стеку
+    return 1;
+}
+
+void print_stack(struct stack* s) {
+    for (int i = 0; i < s->size; i++) {
+        printf("%.2f ", s->values[i]);
+    }
+    printf("\n");
+}
+
+int main() {
+    struct stack mystack;
+    char buffer[BUFFER_SIZE];
+    char operator;
+    float new, a, b, result;
+    init_stack(&mystack);  //обнуляємо стек
+
+    while (fgets(buffer, BUFFER_SIZE, stdin)) {
+        buffer[strcspn(buffer, "\n")] = '\0';
+        if (strlen(buffer) == 0) {
+            printf("no input\n");
+            return 1;
+        }
+
+        if (sscanf(buffer, "%f", &new) == 1) {  //спроба прочитати число
+            if (!push_stack(&mystack, new)) return 1;
+            print_stack(&mystack);
+        }else if (sscanf(buffer, " %c", &operator) == 1 && strchr("+-*/", operator)) {
+            if (!pop_stack(&mystack, &b) || !pop_stack(&mystack, &a)) return 1;
+
+            switch (operator) {
+                case '+': result=a+b; break;
+                case '-': result=a-b; break;
+                case '*': result=a*b; break;
+                case '/':
+                    if (b == 0) {
+                        printf("division by zero\n");
+                        return 1;
+                    }
+                    result = a/b;
+                    break;
+            }
+
+            if (!push_stack(&mystack, result)) {
+                return 1;
+            }
+            print_stack(&mystack);
+        } else {
+            printf("invalid input\n");
+            return 1;
+        }
+    }
+    printf("no input\n");
+    return 1;
+}
\ No newline at end of file