CSE 428: Quizzes

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[Pts 2] A location is free (not allocated) in the current environment if (only one answer, please)
1. it does not have a value
2. it is not associated to any identifier
3. it does not occur in the left-hand side of an assignment
4. it does not occur in the right-hand side of an assignment
[Pts 2] What is the result of the evaluation of an expression in an imperative language (only one answer, please)
1. a new location
2. an environment
3. a value
4. a parse tree
[Pts 2] What is the result of the evaluation of a command in an imperative language (only one answer, please)
1. a new program
2. a new location
3. a state
4. an environment
[Pts 2] Consider the following command in the mini-imperative language
```
   begin
     x
     in x := 5;
        begin y in y := x; x := y; y := 1 + x  end;
        c
   end
```
What is the value of x at the beginning of the execution of c?
Note: an equivalent fragment of code in C++ would be:
```
   int x = 5; { int y; y = x; x = y; y = 1 + x; } c;
```
Answer: 5
[Pts 2] Consider the following command in the mini-imperative language
```
   begin
     x
     in x := 1;
        begin x in x := 2; x := x + 1 end;
        c
   end
```
What is the value of x at the beginning of the execution of c?
Note: an equivalent fragment of code in C++ would be:
```
   int x = 1; { int x = 2; x = x + 1; } c;
```
Answer: 1