Purpose of Implicit Conversions

1#include <iostream>
2using namespace std;
3
4int main() {
5  // In math: 5 + 3.14 is perfectly normal
6  float Sum{5 + 3.14f};
7  cout << "5 + 3.14 = " << Sum << "\n";
8
9  // We often mix whole numbers and decimals
10  // Starting position
11  float PlayerX{10};         
12  // Move half a unit right
13  PlayerX = PlayerX + 0.5f;  
14  cout << "Player position: " << PlayerX;
15}

1int main() {
2  // Without implicit conversions, we'd need
3  // explicit conversions everywhere
4  float Sum{static_cast<float>(5) + 3.14f};  
5  float PlayerX{static_cast<float>(10)};  
6}

1#include <iostream>
2using namespace std;
3
4int main() {
5  int Score{100};
6
7  // This is clear and simple
8  if (Score) {
9    cout << "Player has points!\n";
10  }
11
12  // Without implicit conversions, we'd need:
13  if (Score > 0) {
14    cout << "This is more complicated than"
15      " needed!";
16  }
17}

1int main() {
2  // This could lose data - C++ prevents it
3  int DangerousInt{3.14f};  
4
5  // We have to be explicit if we really want to do this
6  int IntentionalInt{static_cast<int>(3.14f)};
7}