diff --git a/du3/program.c b/du3/program.c
new file mode 100644
index 0000000..7fe22cb
--- /dev/null
+++ b/du3/program.c
@@ -0,0 +1,80 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+
+#define SIZE 10
+
+
+struct stack{
+	float values[SIZE];
+	int size;
+};
+void print(struct stack *s)
+{
+	for(int i = 0; i < s ->values[i]){
+		printf("%.2f ", s->values[i]);		
+	}
+	printf("\n");
+}
+void push(struct stack *s, float value)
+{
+    assert(s->size < SIZE); 
+    s->values[s->size] = value;
+    s->size += 1;
+}
+float pop(struct stack *s)
+{
+    assert(s->size > 0);
+    s->size -= 1;
+    return s->values[s->size];
+}
+int main(){
+	struct stack mystack;
+	mamset(&mystack,0,sizeof(struct stack));
+	char x[100];
+
+	while(fgets(x, 100, stdin)){
+		x[strcspn(x, "\n")] = 0;
+		if (strlen() == 0) continue;
+		char *endptr;
+		float num = strtof(x, &endptr);
+
+		if (*endptr == "\0") { // je cislo
+			if(mystack.size >= SIZE) {
+				fprintf(stderr," plne \n");
+				return 1;
+			}	
+		push(&mystack,num);
+		}
+		else if(stlen(x) == 1 && strchr("+-/", x[0])) {
+			if (mystack.size < 2){
+				fprint(stderr, "malo cisel \n");
+				return 1;
+			}	
+			float a = pop(&mystack);
+			float b = pop(&mystack);
+			float result =   0;
+			switch(x[0]){
+				case '+': result = a + b; break;
+				case '-': result = a - b; break;
+				case '*': result = a * b;break;
+				case '/':
+					  if(b == 0){
+						fprintf(strderr, "nule pr ideleni \n");
+						return 1;
+					  }
+				resut = a / b;
+	       			break;			
+			}
+		push(&mystak,result);
+		}
+		else{
+			fprintf(stderr, " zly vstup \n");
+			return 1;
+		}
+		print (&mystack);
+	}
+	
+	return 0;	
+}