C++ Basic MCQ Questions And Answers

1. Which of the following cannot be used as identifiers?

Letters

Digits

Underscores

Spaces

Spaces cannot be used as identifiers because in most programming languages, identifiers are used to represent variables, functions, or other entities in the code. Spaces are not allowed because they can cause ambiguity and confusion in the code. Instead, developers typically use underscores or camel case to separate words within an identifier.

Explanation

Spaces cannot be used as identifiers because in most programming languages, identifiers are used to represent variables, functions, or other entities in the code. Spaces are not allowed because they can cause ambiguity and confusion in the code. Instead, developers typically use underscores or camel case to separate words within an identifier.

2. The difference between x and 'x' is

The first one refers to a variable whose identifier is x and the second one refers to the character constant x

The first one is a character constant x, and second one is the literal string x

Both are same

None of above

The correct answer is that the first one refers to a variable whose identifier is x and the second one refers to the character constant x. This means that the first one is a variable that can hold a value, while the second one is a specific character constant.

Explanation

The correct answer is that the first one refers to a variable whose identifier is x and the second one refers to the character constant x. This means that the first one is a variable that can hold a value, while the second one is a specific character constant.

3. A variable is/are

A string that varies during program execution

A portion of memory to store a determined value

Those numbers that are frequently required in programs

None of these

The correct answer is "A portion of memory to store a determined value". In programming, a variable is a named location in memory that holds a value. It is used to store and manipulate data during program execution. Variables can hold different types of values such as numbers, strings, or boolean values, and their values can change throughout the program. They provide a way to store and access data efficiently, making it easier to work with and manipulate information in a program.

Explanation

The correct answer is "A portion of memory to store a determined value". In programming, a variable is a named location in memory that holds a value. It is used to store and manipulate data during program execution. Variables can hold different types of values such as numbers, strings, or boolean values, and their values can change throughout the program. They provide a way to store and access data efficiently, making it easier to work with and manipulate information in a program.

4. In an assignment statement

The value must always be a variable.

The value might be a constant, a variable, an expression, or any combination of these.

The assignment always takes place from right to left and never the other way.

All of above

The correct answer is "All of above". This is because in an assignment statement, the value can be a constant, a variable, an expression, or any combination of these. The assignment always takes place from right to left and never the other way. Therefore, all the statements mentioned in the options are correct.

Explanation

The correct answer is "All of above". This is because in an assignment statement, the value can be a constant, a variable, an expression, or any combination of these. The assignment always takes place from right to left and never the other way. Therefore, all the statements mentioned in the options are correct.

5. Regarding the following statement, which of the statements is true?

const int pathwidth=100;

Declares a variable pathwidth with 100 as its initial value

Declares a construction pathwidth with 100 as its initial value

Declares a constant pathwidth whose value will be 100

Constructs an integer type variable with pathwidth as identifier and 100 as value

The given statement "const int pathwidth=100;" declares a constant variable named pathwidth with an initial value of 100.

Explanation

The given statement "const int pathwidth=100;" declares a constant variable named pathwidth with an initial value of 100.

6. Which of the following statement is true?

String Literals can extend to more than a single line of code by putting a backslash sign at the end of each unfinished line.

You can also concatenate several string constants, separating them by one or several blank spaces, tabulators, newlines, or any other valid blank character.

If we want the string literal to explicitly made of wide characters, we can precede the constant with the L prefix.

All of above

All of the statements given are true. String literals can extend to more than a single line of code by using a backslash at the end of each unfinished line. Multiple string constants can be concatenated by separating them with blank spaces, tabulators, newlines, or any other valid blank character. If we want the string literal to be explicitly made of wide characters, we can use the L prefix. Therefore, the correct answer is "All of above."

Explanation

All of the statements given are true. String literals can extend to more than a single line of code by using a backslash at the end of each unfinished line. Multiple string constants can be concatenated by separating them with blank spaces, tabulators, newlines, or any other valid blank character. If we want the string literal to be explicitly made of wide characters, we can use the L prefix. Therefore, the correct answer is "All of above."

7. Which of the following identifiers is invalid?

Papername

Writername

Typename

Printname

The identifier "Typename" is invalid because it starts with an uppercase letter, which is not allowed in most programming languages. Identifiers usually start with a lowercase letter or an underscore.

Explanation

The identifier "Typename" is invalid because it starts with an uppercase letter, which is not allowed in most programming languages. Identifiers usually start with a lowercase letter or an underscore.

8. Which of the following cannot be used as a valid identifier?

Bitand

Bittand

Biand

Band

The identifier "bitand" cannot be used as a valid identifier because it is a reserved keyword in many programming languages, including C++, C#, and Java. Reserved keywords have a predefined meaning in the language and cannot be used as identifiers for variables, functions, or other elements in the code. Using "bitand" as an identifier would result in a syntax error.

Explanation

The identifier "bitand" cannot be used as a valid identifier because it is a reserved keyword in many programming languages, including C++, C#, and Java. Reserved keywords have a predefined meaning in the language and cannot be used as identifiers for variables, functions, or other elements in the code. Using "bitand" as an identifier would result in a syntax error.

9. Which of the following is not a valid escape code?

\t

\v

\f

\w

not-available-via-ai

Explanation

not-available-via-ai

10. Regarding #difine, which of the following statement is false?

It is not a C++ statement but the directive for the preprocessor.

This does not require a semicolon at the end of line.

It is a C++ statement that declares a constant in C++.

None of the above

The statement "It is a C++ statement that declares a constant in C++" is false. The correct answer is that #define is not a C++ statement but the directive for the preprocessor. #define is used to define constants or macros in C++ and is processed by the preprocessor before the actual compilation of the code. It does not require a semicolon at the end of the line.

Explanation

The statement "It is a C++ statement that declares a constant in C++" is false. The correct answer is that #define is not a C++ statement but the directive for the preprocessor. #define is used to define constants or macros in C++ and is processed by the preprocessor before the actual compilation of the code. It does not require a semicolon at the end of the line.