ex-05: Initial solution

exercise-05-calculator/main.c

@@ -0,0 +1,47 @@
+#include <limits.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main() {
+  printf("Zadejte vzorec:\n");
+
+  double num1, num2;
+  char op;
+  if (scanf(" %lf %c %lf = ", &num1, &op, &num2) != 3) {
+    printf("Nespravny vstup.\n");
+    return EXIT_FAILURE;
+  }
+
+  if (op != '+' && op != '-' && op != '*' && op != '/') {
+    printf("Nespravny vstup.\n");
+    return EXIT_FAILURE;
+  }
+
+  if (op == '/' && num2 == 0) {
+    printf("Nespravny vstup.\n");
+    return EXIT_FAILURE;
+  }
+
+  double result = 0;
+  switch (op) {
+  case '+':
+    result = num1 + num2;
+    break;
+  case '-':
+    result = num1 - num2;
+    break;
+  case '*':
+    result = num1 * num2;
+    break;
+  case '/':
+    result = floor(num1 / num2);
+    break;
+  };
+
+  if (result > INT_MAX) {
+    printf("%.1e\n", result);
+  } else {
+    printf("%ld\n", (long)result);
+  }
+}