diff --git a/cv3/program.c b/cv3/program.c
index ba96e19..6acbf18 100644
--- a/cv3/program.c
+++ b/cv3/program.c
@@ -2,114 +2,111 @@
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
-#include <ctype.h>
 
 #define STACK_SIZE 10
 
+
 struct stack {
     float values[STACK_SIZE];
     int size;
 };
 
-void push_stack(struct stack* stack, float value);
-float pop_stack(struct stack* stack);
-void print_stack(struct stack* stack);
-int is_number(const char* str);
 
-int main() {
-    struct stack mystack;
-    memset(&mystack, 0, sizeof(struct stack)); 
-
-    char input[50];
-    int empty_input = 0;  
-    
-    while (1) {
-        
-        if (!fgets(input, sizeof(input), stdin)) {
-            break; 
-        }
-
-        input[strcspn(input, "\n")] = 0;  
-
-        if (strlen(input) == 0) {
-            empty_input = 1;  
-            break;
-        }
-
-        if (is_number(input)) {
-            float value = atof(input);
-            push_stack(&mystack, value);
-        } else if (strlen(input) == 1 && strchr("+-*/", input[0])) {
-            if (mystack.size < 2) {
-                fprintf(stderr, "Error: Not enough values in stack.\n");
-                exit(EXIT_FAILURE);
-            }
-            float b = pop_stack(&mystack);
-            float a = pop_stack(&mystack);
-            float result;
-
-            switch (input[0]) {
-                case '+':
-                    result = a + b;
-                    break;
-                case '-':
-                    result = a - b;
-                    break;
-                case '*':
-                    result = a * b;
-                    break;
-                case '/':
-                    if (b == 0) {
-                        fprintf(stderr, "Error: Division by zero.\n");
-                        exit(EXIT_FAILURE);
-                    }
-                    result = a / b;
-                    break;
-                default:
-                    fprintf(stderr, "Error: Invalid operator.\n");
-                    exit(EXIT_FAILURE);
-            }
-            push_stack(&mystack, result);
-        } else {
-            fprintf(stderr, "Error: Invalid input.\n");
-            exit(EXIT_FAILURE);
-        }
-
-        print_stack(&mystack);
-    }
-
-   
-    if (empty_input) {
-        printf("no input\n");
-    }
-
-    return 0;
+void init_stack(struct stack* s) {
+    memset(s, 0, sizeof(struct stack));
 }
 
 
-
-void push_stack(struct stack* stack, float value) {
-    assert(stack->size < STACK_SIZE); 
-    stack->values[stack->size] = value;
-    stack->size += 1;
+void push_stack(struct stack* s, float value) {
+    assert(s->size < STACK_SIZE); 
+    s->values[s->size] = value;
+    s->size += 1;
 }
 
-float pop_stack(struct stack* stack) {
-    assert(stack->size > 0); 
-    stack->size -= 1;
-    return stack->values[stack->size];
+
+float pop_stack(struct stack* s) {
+    assert(s->size > 0); 
+    s->size -= 1;
+    return s->values[s->size];
 }
 
-void print_stack(struct stack* stack) {
-    
-    for (int i = 0; i < stack->size; i++) {
-        printf("%.2f ", stack->values[i]);
+
+void print_stack(struct stack* s) {
+    for (int i = 0; i < s->size; i++) {
+        printf("%.2f ", s->values[i]);
     }
     printf("\n");
 }
 
-int is_number(const char* str) {
-    char* endptr;
-    strtod(str, &endptr);
-    return *endptr == '\0' && endptr != str;
+int main() {
+    struct stack mystack;
+    init_stack(&mystack);
+
+    char input[256];
+    while (1) {
+        printf("Zadajte číslo alebo operáciu (+, -, *, /): ");
+        if (!fgets(input, sizeof(input), stdin)) {
+            break; 
+        }
+
+        
+        input[strcspn(input, "\n")] = 0;
+
+        
+        char* endptr;
+        float value = strtof(input, &endptr);
+        if (endptr != input) { 
+            push_stack(&mystack, value);
+            print_stack(&mystack);
+            continue;
+        }
+
+        
+        if (strcmp(input, "+") == 0) {
+            if (mystack.size < 2) {
+                printf("Chyba: Nedostatok hodnôt v zásobníku.\n");
+                break;
+            }
+            float b = pop_stack(&mystack);
+            float a = pop_stack(&mystack);
+            push_stack(&mystack, a + b);
+            print_stack(&mystack);
+        } else if (strcmp(input, "-") == 0) {
+            if (mystack.size < 2) {
+                printf("Chyba: Nedostatok hodnôt v zásobníku.\n");
+                break;
+            }
+            float b = pop_stack(&mystack);
+            float a = pop_stack(&mystack);
+            push_stack(&mystack, a - b);
+            print_stack(&mystack);
+        } else if (strcmp(input, "*") == 0) {
+            if (mystack.size < 2) {
+                printf("Chyba: Nedostatok hodnôt v zásobníku.\n");
+                break;
+            }
+            float b = pop_stack(&mystack);
+            float a = pop_stack(&mystack);
+            push_stack(&mystack, a * b);
+            print_stack(&mystack);
+        } else if (strcmp(input, "/") == 0) {
+            if (mystack.size < 2) {
+                printf("Chyba: Nedostatok hodnôt v zásobníku.\n");
+                break;
+            }
+            float b = pop_stack(&mystack);
+            float a = pop_stack(&mystack);
+            if (b == 0) {
+                printf("Chyba: Delenie nulou.\n");
+                break;
+            }
+            push_stack(&mystack, a / b);
+            print_stack(&mystack);
+        } else {
+            printf("Chyba: Neplatný vstup.\n");
+            break;
+        }
+    }
+
+    return 0;
 }