Question

In the Pascal programming language, the

If-Statement

is defined as follows:

Consider the following statement, and then answer the related questions:

<If-Statement> ::= If <Condition> Then <Statement> [Else<Statement>] <Statement> ::= <If-Statement> | <While-Statement> | <For-Statement> | <Assignment-Statement>

<Condition> ::= [not] <Condition> | [not] <BooleanVariable> | <Variable> <Operator> Variable> |

<Variable> <Operator> <Expression> | < Expression > <Operator> <Variable> |

< Expression > <Operator> < Expression> | < Expression > <Operator> < Literal > |

<Variable> <Operator> < Literal >

<Operator> ::= = | < | <= | > | >= | <>

Consider the following statement, and then answer the related questions:

If C1 Then If C2 Then S1 Else S2

7a. Explain the phenomenon called ambiguity.

7b. Using derivation tree(s) or otherwise, show that the statement is ambiguous.

Draw a picture.

7c. This kind of ambiguity exists in C++ as well as Java. Explain and demonstrate how it can

be avoided by the programmer in these two languages.

Answer 1