works as described

pocket_calc.c

@@ -0,0 +1,89 @@
+#include <stdio.h>
+#include <string.h>
+#include <float.h>
+#include <stdbool.h>
+#define FIRST_OPTION 1
+#define SECOND_OPTION 2
+#define THIRD_OPTION 3
+#define FOURTH_OPTION 4
+#define FIFTH_OPTION -1
+
+int main(int argc, char* argv[])
+{
+    int user_choice;
+    while (true)
+    {
+        bool dont_pass = true;
+        printf("Choose one of the following operations:\n");
+        printf("\tAdd (%d)\n", FIRST_OPTION);
+        printf("\tSubtract (%d)\n", SECOND_OPTION);
+        printf("\tMultiply (%d)\n", THIRD_OPTION);
+        printf("\tDivide (%d)\n", FOURTH_OPTION);
+        printf("\tStop program (%d)\n", FIFTH_OPTION);
+        do
+        {
+            printf("Enter your choice: ");
+            scanf("%d", &user_choice);
+            dont_pass = user_choice < FIFTH_OPTION || user_choice > FOURTH_OPTION || user_choice == 0;
+            if (dont_pass)
+            {
+                printf("Input not allowed, please try again\n");
+            }
+            
+        } while (dont_pass);
+
+        if(user_choice == -1) return 0;
+
+        double first_operand;
+        double second_operand;
+        dont_pass = true;
+        do
+        {
+            printf("Please enter the first operand: ");
+            scanf("%lf", &first_operand);
+            printf("Please enter the second operand: ");
+            scanf("%lf", &second_operand);
+            if(user_choice == FOURTH_OPTION && second_operand == 0)
+            {
+                printf("Division by zero\n");
+            }
+            else if (first_operand < DBL_MIN || second_operand < DBL_MIN)
+            {
+                printf("Number underflow\n");
+            }
+            else if(first_operand > DBL_MAX || second_operand > DBL_MAX)
+            {
+                printf("Number overflow\n");
+            }
+            else
+            {
+                dont_pass = false;
+            }
+        }
+        while (dont_pass);
+
+        double result;
+        switch(user_choice)
+        {
+            case FIRST_OPTION:
+                result = first_operand + second_operand;
+                printf("The result is %.3f\n", result);
+                break;
+            case SECOND_OPTION:
+                result = first_operand - second_operand;
+                printf("The result is %0.3f\n", result);
+                break;
+            case THIRD_OPTION:
+                result = first_operand * second_operand;
+                printf("The result is %0.3f\n", result);
+                break;
+            case FOURTH_OPTION:
+                result = first_operand / second_operand;
+                printf("The result is %2.3f\n", result);
+                break;
+            default:
+                return 0;
+        }
+    }
+    return 0;
+}