Multithreading: 3.Mutex

When we execute the below code. The output would appear random. We are trying to print 1 to 9 from main and 10 to 19 from the thread.

The output looks like below

threadMain101
threadMain112
threadMain123
threadMain134
threadMain145
threadMain156
threadMain167
threadMain178
threadMain189
thread19

The output looks haphazard and not understandable. This is because both the main thread and the thread t are fighting for the common resource cout. We have to make a change in our code to control the access of cout. meaning if one thread is accessing cout, other thread has to simply wait for access.
We use std::mutex lock and unlock methods to do that.

below is the output after using mutex

thread:10
thread:11
thread:12
thread:13
thread:14
thread:15
thread:16
thread:17
thread:18
thread:19
Main:1
Main:2
Main:3
Main:4
Main:5
Main:6
Main:7
Main:8
Main:9