C++ Essentials

Inputs and outputs

#include <iostream>
using namespace std;

int main(){
    cout << "Hello, World!" << endl;
    return 0;
}

• The above code can also be simplified as below:

  int main(){
      printf("Hello, World!")
      return 0;
  }

• To read a user input in C++, cin is used as shown below:

  int main(){
      string some_user_input;
      cin >> some_user_input;
      cout << "User entered " << some_user_input << endl;
      return 0;
  }

• There are instances when you want to take in numerous user inputs. scanf and printf are used in such cases:

  #include <iostream>
  #include <cstdio>
  using namespace std;
  
  int main(){
      int integer;
      int64_t long_int;
      char character;
      float float_num;
      double double_num; 
      scanf("%d %ld %c %f %lf", &integer, &long_int, &character, &float_num, &double_num);
      printf("%d\n%ld\n%c\n%f\n%lf", integer, long_int, character, float_num, double_num);
      return 0;
    }

• A sample output of the above program is shown below:

  3
  12345678912345
  a
  334.230
  14049.304930000