io_streams.md

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I/O streams

Streams are part of STL

STL stands for Standard Template Library We're gonna talk about it a lot!

📺 Watch the related YouTube video!

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Prerequisites:

• Working with terminal
• Hello world dissection
• Variables of fundamental types

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Disclaimer

• This lecture is beginner friendly
• There are some best practices that would use different types, but those require more in-depth understanding and will be covered later
• What you see on this slide is the best practice until this point in the course 😉

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Special symbols used in slides

• 🎨 - Style recommendation
• 🎓 - Software design recommendation
• 😱 - Not a good practice! Avoid in real life!
• ✅ - Good practice!
• ❌ - Whatever is marked with this is wrong
• 🚨 - Alert! Important information!
• 💡 - Hint or a useful exercise
• 🔼1️⃣7️⃣ - Holds for this version of C++(here, 17) and above
• 🔽1️⃣1️⃣ - Holds for versions until this one C++(here, 11)

Style (🎨) and software design (🎓) recommendations mostly come from Google Style Sheet and the CppCoreGuidelines

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I/O streams for input and output

• Handle stdin, stdout and stderr:
  • std::cin --- maps to stdin
  • std::cout --- maps to stdout
  • std::cerr --- maps to stderr
• #include <iostream> to use I/O streams
• Easier to use than std::printf but slower
• 💡 We will cover a better way for logging in the future but streams are totally good enough for now 👌

#include <iostream>
int main() {
  int some_number{};
  std::cin >> some_number;
  std::cout << "number = " << some_number << std::endl;
  std::cerr << "boring error message" << std::endl;
  return 0;
}

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