Selection

• one way statement 

  one way statement usually used in the program which is there have only one choice. in other word, "take it or leave it".
  e.g:
  "write a C++ program that will display a message "pass" if the students mark is more than 50." - In this situation, the output is only execute one statement , and if the user input mark below than 50, no statement are there.
  
      if(mark>50)
  
  cout<<"pass";   

• two way statement 

  two way statement is used when there have two option. 
  e.g:
  "write a C++ program that will display a message "pass" if the student mark is more than 50. Otherwise, display "fail". - in this stituation, there are two option.
  
  
  if (mark>50)
  cout<<"pass";
  else if(mark<=50)
  cout <<"fail";
  
  

• multiple way statement 

  But, when we have more than two option, we need to write a multiple way statement..
  e.g:
   " write a C++ program that  will display students grade. A - 80 and above, B - 70 and above, C - 50 and above, D - 40 and above, else, grade is F". - in this situation, we have more than 2 option (5 options).
  
  
  if (mark>=80)
  grade = 'A';
  else if(mark>=70)
  grade = 'B';
  else if(mark>=50)
  grade = 'C';
  else if(mark>=40)
  grade = "D';
  else
  grade = 'F';
  
  
  cout<<grade;  

• Nested statement