chore: implementation of a calculator

exercises/calculator.cpp

@@ -10,3 +10,76 @@
   Multiplication: 8
   Division: 2
 */
+
+#include <iostream>
+using namespace std;
+#define EXIT_SUCCESS 0
+
+
+float switchOp(int x, int a, int b){
+  float result;
+
+  switch(x){
+    case 1:{
+      cout << endl << "SUM = ";
+      result = a + b;
+      break;
+    }
+
+    case 2:{
+      cout << endl << "Difference = ";
+      result = a - b;
+      break;
+    }
+
+    case 3:{
+      cout << endl << "Multiplication = ";
+      result = a * b;
+      break;
+    }
+
+    case 4:{
+      cout << endl << "Division = ";
+      result = a / b;
+      break;
+    }
+  }
+  return result;
+}
+
+void operations(float a, float b){
+
+  int op;
+
+  while(true){
+
+    cout << endl << "Select the operation: " << endl << "1) SUM" << endl << "2)Difference" << endl << "3)Multiplication" << endl << "4)Division" << endl;
+    cin >> op;
+
+    if(op <1 || op >4){
+      cerr << "Wrong choice, please select a valid operation number [1-4]" << endl;
+    }
+
+    else if(op == 4 && b == 0){
+      cerr << "Can't divide a number for 0, please select another operation" << endl;
+    }
+
+    else{
+      break;
+    }
+  }  
+  cout << switchOp(op, a, b) << endl << endl;
+}
+
+int main(){
+
+  float a,b;
+  cout << "Insert the first number: ";
+  cin >> a;
+  cout << endl << "Insert second number: ";
+  cin >> b;
+
+  operations(a, b);
+
+  return EXIT_SUCCESS;
+}