Brainiest to best java coding , can you tell me what switch and case does using the example below?

public void setquiz(int quiz,, int grade)
{
switch(quiz)
{
case 1: grade1 = grade;
break;
case 2: grade2 = grade;
break;
}
}

The switch statement is an n-way branch. An n-way branch can branch to any of an arbitrary number ( n ) of branches. An if statement can branch two ways, whether the condition is true or false.

The example you gave is a great example of how how code is written can make the code make sense or not.

public void setQuiz( int quiz, int grade )
{
  switch( quiz )
  {
    case 1: // if quiz == 1
      grade1 = grade; //where was grade1 declared?
      break;  // otherwise execution will continue through the next case block
    case 2: // if quiz == 2
      grade2 = grade;
      break;
  }
}

The variable named in the switch statement is tested against each case statement and whichever case statement's value matches, the rest of the switch statement's code is executed. (That's why the break statements are needed) Usually switch statements are written with a default case at the end as a "catchall".