diff --git a/main.cpp b/main.cpp
index 444c48f..22a3ea5 100644
--- a/main.cpp
+++ b/main.cpp
@@ -34,22 +34,36 @@ int main() {
 
     Vector b = {24, 6, 1, 2};
 
+    for (int i = 0; i < b.size(); i++) {
+        if (b[i] < 0) {
+            std::cout << "Error: method is not applicable" << std::endl;
+            return 1;
+        }
+    }
+
     //Matrix test = {{1, -1, -2}, {1, 1, -2}, {1, -1, 2}};
 
     //showMatrix(test);
     
 
     Result result = Simplex(C, A, b, 0.1, true);
-    if(result.state == bounded) {
 
+
+
+    if(result.state == bounded) {
         if(result.solution == nullptr) {
-            // TODO: error
+            std::cout << "Error: no solution value is returned" << std::endl;
+            return 1;
         }
         std::cout << *result.solution << std::endl;
         std::cout << result.objective_fucntion_value << std::endl;
 
         delete result.solution;
     }
+    else {
+        std::cout << "Error: unbounded" << std::endl;
+        return 1;
+    }
     //std::cout << "asdasd" << std::endl;
 
     return 0;