C++ beginner, execution window disappears quickly

Question

I am a beginner in C++ and I was trying to write a program that finds the average of two numbers, but when I run the program, the window disappears without allowing me to se

Answer 1

Solution #0 (proper):
Run program from shell (cmd.exe, bash)

Solution #1 (proper):
Run program from orthodox file manager. Far Manager or midnight commander.

Solution #2 (alternative);
Redirect output to file. program.exe >file.txt from command line.

Solution #3 (improper):
Launch message box, use "sleep"/"Sleep" to delay program termination.

Solution #4 (improper):
Request user input at the end of program.

Solution #5 (improper):
Set breakpoint on "return 0", debug the program.

Solution #6 (windows+msvc):
Launch program from msvc by Ctrl+F5 using debug build. You'll get "press key to continue" prompt.