1. What are the data types included in Pascal?
- Data type defines a range of values that a variable can store. It also includes set of operations that are performed on different data types.
- There is predefined data type as:
- Integers are the whole numbers that allow only the numbers to be written without any decimal points.
- The real numbers are treated as floating point numbers that can have decimals as well with the non-decimal digits.
- Boolean data types define only the two values either it is true or false. In programming it can be used when there is a decision need to be made between the two entities.
- Char data type allows the single character to be written in an ordered form with the ordered character set.
2. What are sub-range types and sub-types in Pascal language?
- The sub-range allows defining the implementation of the functions that provides the data conversions to be performed on the data types like real to integer, etc.
- The sub-ranges of the data type can be made using the ordinary data type which will be as follows:
var
x : 1..10;
y : 'a'..'z';
z : Apple..Mango;
- Set provides a way to group the things and the objects using the mathematical algorithm. The set can hold the values that will make it faster.
- The set types are used to have a set in which there are some values that needs to be defined.
- This is shown as:
var
Set1 : set of 1..10;
Set2 : set of 'a'..'z';
Set3 : set of Apple..Mango;
- Set operators can be used to implement the machine code operations that involve smaller domains.
3.What are the different pointer types used in pascal?
- Record pointers are the pointers that allow the recording of the node and the sub-fields that are being used.
- Reference pointers: Pointers are the reference to the dynamically created variables that doesn’t allow the references to be done in static or local variables.
- Associate type pointers: Pointers have an associated data type with them so that one type can be check for compatibility with another type.
- It helps in eliminating the security concern and allows easy implementation of the pointer used in the language.
- This allows the risk to be removed in case of using the dangling pointers and it dynamically allows the use of Dispose function that manages the risk.
- Example of the pointer is as follows:
type
pNode = ^Node;
Node = record
a : integer;
b : char;
c : pNode {extra semicolon not strictly required}
end;
var
NodePtr : pNode;
IntPtr : ^integer;
- The NodePtr is a variable pointer that is pointing to the data type of Node that is a record. Pointers are used before they are declared.
4. What is the control structure used by Pascal?
- Pascal uses structure programming language to display the flow of control in an structured manner.
- It uses the goto statement/command as standard statements that allow the control to be given to the main program in a recursive manner.
- It provides more easy way to represent them without using the semicolon to end the statements written in one line.
- It uses loops as a control structure to represent the statements and uses assignment operators to assign the values to the variables.
- The example of it is as follows:
while (a <> b) do WriteLn('Waiting');
if (a > b) then WriteLn('Condition met')
else WriteLn('Condition not met');
for i := 1 to 10 do
WriteLn('Iteration: ', i);
repeat
a := a + 1
until (a = 10);
case i of
0 : Write('zero');
1 : Write('one');
2 : Write('two');
else begin Write('?'); exit; end
end;
5. What are the procedures and functions used in Pascals?
- Procedures and functions both are different in their own sense and both are required the program construct.
- Procedures and functions are the main part of the logical block and they can be nested to any depth in the code.
- It has its own declarations like goto labels, constants, types, variables and other defining entity that allow them to keep every function in order.
- The ordering of the functions are required to allow the efficient compilation process using the single pass.
- The example of it is shown below:
program Mine(output);
var i : integer;
procedure Print(var j : integer);
begin
...
end;
begin
...
Print(i);
end
6. Why are semicolons as statement separators used in Pascal?
- Pascal uses the semicolon as separators which have been taken from one of the features of the ALGOL language.
- Semicolon as a statement terminator is used so that other statements can be preceded or other statements can be executed.
- There is no semicolon that is required before the keyword end as it defines the record type declaration.
- A block and a case statement also don’t require any semicolon as they needs to be carried on and gets executed.
- The semicolon in the language is not used immediately before the keyword else if the “if” statement is used as, the else statement is treated a single statement.
- The semicolon gets applied to the sequence of statement that is written in more than one statement.
7. Why Pascal is used without extensions?
- Pascal uses extensions to extend the features used in the language and to overall implementation of the code.
- The implementation is standardized to many processors and implementations when it is possible.
- Program that is coded with the language doesn’t use much extension due to the fact that it doesn’t require high performances.
- Extensions make the program more clean and portable to use by providing the interfaces to be used in programs.
- Library construction has become easy to use due the features of advanced interface and the portability that is being increased.
8. What are the features that make Pascal a good language in modern programming?
- Pascal is a very structured language and uses the control structures like if-else, repeat-until statements, etc.
- It is having different data structures that are included with the records, arrays, files, pointers, etc.
- Pascal provides simplicity and provides a modular approach for machine implementation. It allows the features to be related to the compiler.
- Pascal uses minimum ambiguity to represent the data and its structure it is processed with some exceptions and provides smaller elements with their definitions.
- Pascal provides the exact sizes used by the operands and operators to perform on them. It provides a way to process and use the efficient code.
9. What are the differences between standard Pascal and modern Pascal?
- Modern Pascal uses more securities and fewer ambiguities while programming or coding. Whereas, Standard Pascal have been using less security and more ambiguity while programming or coding.
- Modern Pascal provides backward compatibility by the use of functions and procedures with their parameters. Whereas, standard Pascal doesn’t provide this kind approach and doesn’t follow the backward compatibility.
- Modern Pascal provides Var parameters to be used with the procedures and functions and make advancement over the standard Pascal.
- Modern Pascal provides the definitive type of compatibility with its parameters and the symbols used. Whereas, standard Pascal doesn’t provide anything related to the symbols.
- Modern Pascal allows the removal of the length of the symbol that is limited. Whereas, standard Pascal doesn’t remove the symbol length limit.
10. What are the changes being made in P-machine Pascal?
- P-machine Pascal is the variant of the Pascal and it allows the implementation to be done of standard Pascal language.
- The changes made to the P-machine are as follows:
- Procedures and functions are not treated as parameters in the Pascal language. It also doesn’t simplify the use of it.
- The statements like Goto have no reference targets mainly outside the procedure/function bodies.
- The file types that are in the form of text can be used as an input or output and the special files can be compiled by itself.
- P-machine allows the use of pre-defined identifiers like maxint, round, page, disclose, etc. that are not present.
- Dispose is not being implemented in the P-machine Pascal and is replaced by the “mark” and “release” keywords.
- Data type defines a range of values that a variable can store. It also includes set of operations that are performed on different data types.
- There is predefined data type as:
- Integers are the whole numbers that allow only the numbers to be written without any decimal points.
- The real numbers are treated as floating point numbers that can have decimals as well with the non-decimal digits.
- Boolean data types define only the two values either it is true or false. In programming it can be used when there is a decision need to be made between the two entities.
- Char data type allows the single character to be written in an ordered form with the ordered character set.
2. What are sub-range types and sub-types in Pascal language?
- The sub-range allows defining the implementation of the functions that provides the data conversions to be performed on the data types like real to integer, etc.
- The sub-ranges of the data type can be made using the ordinary data type which will be as follows:
var
x : 1..10;
y : 'a'..'z';
z : Apple..Mango;
- Set provides a way to group the things and the objects using the mathematical algorithm. The set can hold the values that will make it faster.
- The set types are used to have a set in which there are some values that needs to be defined.
- This is shown as:
var
Set1 : set of 1..10;
Set2 : set of 'a'..'z';
Set3 : set of Apple..Mango;
- Set operators can be used to implement the machine code operations that involve smaller domains.
3.What are the different pointer types used in pascal?
- Record pointers are the pointers that allow the recording of the node and the sub-fields that are being used.
- Reference pointers: Pointers are the reference to the dynamically created variables that doesn’t allow the references to be done in static or local variables.
- Associate type pointers: Pointers have an associated data type with them so that one type can be check for compatibility with another type.
- It helps in eliminating the security concern and allows easy implementation of the pointer used in the language.
- This allows the risk to be removed in case of using the dangling pointers and it dynamically allows the use of Dispose function that manages the risk.
- Example of the pointer is as follows:
type
pNode = ^Node;
Node = record
a : integer;
b : char;
c : pNode {extra semicolon not strictly required}
end;
var
NodePtr : pNode;
IntPtr : ^integer;
- The NodePtr is a variable pointer that is pointing to the data type of Node that is a record. Pointers are used before they are declared.
4. What is the control structure used by Pascal?
- Pascal uses structure programming language to display the flow of control in an structured manner.
- It uses the goto statement/command as standard statements that allow the control to be given to the main program in a recursive manner.
- It provides more easy way to represent them without using the semicolon to end the statements written in one line.
- It uses loops as a control structure to represent the statements and uses assignment operators to assign the values to the variables.
- The example of it is as follows:
while (a <> b) do WriteLn('Waiting');
if (a > b) then WriteLn('Condition met')
else WriteLn('Condition not met');
for i := 1 to 10 do
WriteLn('Iteration: ', i);
repeat
a := a + 1
until (a = 10);
case i of
0 : Write('zero');
1 : Write('one');
2 : Write('two');
else begin Write('?'); exit; end
end;
5. What are the procedures and functions used in Pascals?
- Procedures and functions both are different in their own sense and both are required the program construct.
- Procedures and functions are the main part of the logical block and they can be nested to any depth in the code.
- It has its own declarations like goto labels, constants, types, variables and other defining entity that allow them to keep every function in order.
- The ordering of the functions are required to allow the efficient compilation process using the single pass.
- The example of it is shown below:
program Mine(output);
var i : integer;
procedure Print(var j : integer);
begin
...
end;
begin
...
Print(i);
end
6. Why are semicolons as statement separators used in Pascal?
- Pascal uses the semicolon as separators which have been taken from one of the features of the ALGOL language.
- Semicolon as a statement terminator is used so that other statements can be preceded or other statements can be executed.
- There is no semicolon that is required before the keyword end as it defines the record type declaration.
- A block and a case statement also don’t require any semicolon as they needs to be carried on and gets executed.
- The semicolon in the language is not used immediately before the keyword else if the “if” statement is used as, the else statement is treated a single statement.
- The semicolon gets applied to the sequence of statement that is written in more than one statement.
7. Why Pascal is used without extensions?
- Pascal uses extensions to extend the features used in the language and to overall implementation of the code.
- The implementation is standardized to many processors and implementations when it is possible.
- Program that is coded with the language doesn’t use much extension due to the fact that it doesn’t require high performances.
- Extensions make the program more clean and portable to use by providing the interfaces to be used in programs.
- Library construction has become easy to use due the features of advanced interface and the portability that is being increased.
8. What are the features that make Pascal a good language in modern programming?
- Pascal is a very structured language and uses the control structures like if-else, repeat-until statements, etc.
- It is having different data structures that are included with the records, arrays, files, pointers, etc.
- Pascal provides simplicity and provides a modular approach for machine implementation. It allows the features to be related to the compiler.
- Pascal uses minimum ambiguity to represent the data and its structure it is processed with some exceptions and provides smaller elements with their definitions.
- Pascal provides the exact sizes used by the operands and operators to perform on them. It provides a way to process and use the efficient code.
9. What are the differences between standard Pascal and modern Pascal?
- Modern Pascal uses more securities and fewer ambiguities while programming or coding. Whereas, Standard Pascal have been using less security and more ambiguity while programming or coding.
- Modern Pascal provides backward compatibility by the use of functions and procedures with their parameters. Whereas, standard Pascal doesn’t provide this kind approach and doesn’t follow the backward compatibility.
- Modern Pascal provides Var parameters to be used with the procedures and functions and make advancement over the standard Pascal.
- Modern Pascal provides the definitive type of compatibility with its parameters and the symbols used. Whereas, standard Pascal doesn’t provide anything related to the symbols.
- Modern Pascal allows the removal of the length of the symbol that is limited. Whereas, standard Pascal doesn’t remove the symbol length limit.
10. What are the changes being made in P-machine Pascal?
- P-machine Pascal is the variant of the Pascal and it allows the implementation to be done of standard Pascal language.
- The changes made to the P-machine are as follows:
- Procedures and functions are not treated as parameters in the Pascal language. It also doesn’t simplify the use of it.
- The statements like Goto have no reference targets mainly outside the procedure/function bodies.
- The file types that are in the form of text can be used as an input or output and the special files can be compiled by itself.
- P-machine allows the use of pre-defined identifiers like maxint, round, page, disclose, etc. that are not present.
- Dispose is not being implemented in the P-machine Pascal and is replaced by the “mark” and “release” keywords.
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