fast i/o c++

To implement fast I/O in C++, you can follow the steps below:

  1. Include the necessary libraries: Begin by including the required libraries at the beginning of your code. For fast I/O in C++, you will need to include the <iostream> and <cstdio> libraries.

  2. Disable synchronization between C and C++ streams: To achieve faster I/O, you need to disable the synchronization between C and C++ streams. This can be done by adding the following line of code before the main() function:

std::ios_base::sync_with_stdio(false);
  1. Tie C++ streams with C streams: By default, the C++ streams are tied to the C streams, which can cause a decrease in performance. You can untie them using the following line of code:
std::cin.tie(NULL);
  1. Use printf and scanf for input and output: Instead of using std::cin and std::cout for input and output operations, you can use scanf and printf functions from the <cstdio> library. These functions are generally faster than their C++ counterparts. Here is an example of using scanf and printf for input and output:
int n;
scanf("%d", &n);
printf("The value of n is: %d\n", n);

Note: When using scanf and printf, make sure to use the correct format specifiers based on the data type you are reading or printing.

  1. Ensure proper flushing of output: To ensure that the output is flushed properly, you can use the fflush(stdout) function after using printf to print something. This will prevent any delay in displaying the output.

By following these steps, you can achieve faster input and output in your C++ programs.