Explain a binary semaphore with the help of an example?

An abstract data type (ADT) is a semaphore which defines a nonnegative integer variable that apart from initialization is accessed only by two standard operations i.e.: wait and signal. The typical definition of wait in pseudo code is given as

wait(S){

      while(S<=0)

    ; // not do anything

          S--;

          }

      The classical definitions of signal in pseudocode is signal(S){

          S++;

       }

A  binary  semaphore  is  one  which  only  gets  the  values  0  and  1.  Such semaphores are utilized to implement mutual exclusion.