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Questions and Answers
Which programming language was developed by Martin Richards in 1967?
Which programming language was developed by Martin Richards in 1967?
What was a major reason for the development of the C language in 1972?
What was a major reason for the development of the C language in 1972?
Which organization standardized the C language in 1983?
Which organization standardized the C language in 1983?
What was the primary purpose of standardizing the C language?
What was the primary purpose of standardizing the C language?
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The UNIX operating system's early version was initially developed using which programming language?
The UNIX operating system's early version was initially developed using which programming language?
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Which of the following statements about the C language's history is true?
Which of the following statements about the C language's history is true?
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What describes the primary drawback of the B programming language?
What describes the primary drawback of the B programming language?
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Before the standardization of C, what issue did programmers frequently encounter?
Before the standardization of C, what issue did programmers frequently encounter?
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What does the backspace character do in C?
What does the backspace character do in C?
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In the provided numeric I/O example, what type of value does '%f' represent?
In the provided numeric I/O example, what type of value does '%f' represent?
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Which function would you use to read a string that may contain whitespace?
Which function would you use to read a string that may contain whitespace?
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What will the expression 'sizeof(int)' return in C?
What will the expression 'sizeof(int)' return in C?
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Which of the following correctly outputs the ASCII value of a character in C?
Which of the following correctly outputs the ASCII value of a character in C?
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What character does ' ' represent in C?
What character does ' ' represent in C?
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What is the purpose of the getchar() function in the provided examples?
What is the purpose of the getchar() function in the provided examples?
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In the context, what does '
' do when outputting to the console?
In the context, what does ' ' do when outputting to the console?
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What is the minimum value for the data type 'short int' on a 32-bit computer?
What is the minimum value for the data type 'short int' on a 32-bit computer?
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Which data type occupies 8 bytes of memory on a 32-bit computer?
Which data type occupies 8 bytes of memory on a 32-bit computer?
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What will be the output of the variable 'fnum2' if it is initialized to 93.63?
What will be the output of the variable 'fnum2' if it is initialized to 93.63?
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When defining a variable, what is the correct assignment for a character type variable 'chr' storing 'Z'?
When defining a variable, what is the correct assignment for a character type variable 'chr' storing 'Z'?
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Which of the following is a valid definition for a variable 'num' storing integers?
Which of the following is a valid definition for a variable 'num' storing integers?
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How many bytes does the data type 'char' occupy on a 32-bit computer?
How many bytes does the data type 'char' occupy on a 32-bit computer?
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What is the maximum value for a 32-bit signed integer data type?
What is the maximum value for a 32-bit signed integer data type?
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Which of the following definitions is incorrect for initializing variable 'j' to 0 when declared with 'i'?
Which of the following definitions is incorrect for initializing variable 'j' to 0 when declared with 'i'?
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What does the operator 'a += b' actually perform?
What does the operator 'a += b' actually perform?
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Which relational operator checks if two values are not equal?
Which relational operator checks if two values are not equal?
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What will the value of 'c' be after executing 'c *= a' if 'c' is initially 5 and 'a' is 5?
What will the value of 'c' be after executing 'c *= a' if 'c' is initially 5 and 'a' is 5?
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What is the output of the expression '5 > 3' when evaluated?
What is the output of the expression '5 > 3' when evaluated?
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What is the effect of the operator 'c %= a' if 'c' is 5 and 'a' is 5?
What is the effect of the operator 'c %= a' if 'c' is 5 and 'a' is 5?
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What role do loops play in programming?
What role do loops play in programming?
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Which of the following is not a valid assignment operator in C?
Which of the following is not a valid assignment operator in C?
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What will the result be of the expression '5 <= 3' in C?
What will the result be of the expression '5 <= 3' in C?
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What is the primary function of the sizeof operator in C?
What is the primary function of the sizeof operator in C?
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Which of the following types can the sizeof operator be applied to?
Which of the following types can the sizeof operator be applied to?
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What type of value does the sizeof operator return?
What type of value does the sizeof operator return?
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Which of the following is an example of a unary operator?
Which of the following is an example of a unary operator?
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In the provided arithmetic operators example, what will be the value of c after the operation c = a % b; where a = 9 and b = 4?
In the provided arithmetic operators example, what will be the value of c after the operation c = a % b; where a = 9 and b = 4?
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Which classification of operators does '++' (increment operator) belong to?
Which classification of operators does '++' (increment operator) belong to?
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What is the purpose of the assignment operator in C?
What is the purpose of the assignment operator in C?
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Which of the following statements regarding the sizeof operator is true?
Which of the following statements regarding the sizeof operator is true?
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Study Notes
History of C Language
- C language evolved from ALGOL, which was the first language to use a block structure (introduced in 1960).
- BCPL, derived from ALGOL, was developed in 1967.
- Ken Thompson created the B language, using BCPL, in 1970, both BCPL and B were typeless.
- Dennis Ritchie developed C using BCPL and B at Bell Labs in 1972.
- C's popularity increased with the release of C compilers for commercial use, as well as the increasing popularity of UNIX.
History of UNIX
- Ken Thompson and Dennis Ritchie designed a file system for Bell Labs in 1969 to provide a more convenient programming environment.
- This file system evolved into an early version of the UNIX Operating System.
- The system was implemented on a PDP-7 (in 1971) and PDP-11 computers.
- When trying to create a FORTRAN compiler for the new system, Ken Thompson created the B language.
Why Was C Language Standardized?
- C was standardized by the American National Standards Institute (ANSI) in 1983, and by the International Organization for Standardization (ISO) in 1990.
- The standardization of C ensured compatibility and portability of C programs across different computer systems and hardware platforms.
- Prior to standardization, different versions of C existed with different syntax and libraries, making it difficult to port programs.
Defining Data
- Memory for data types (fundamental and derived) is defined in the following format:
[data type] [variable name],...; - Data is typically defined at the beginning of a function.
- C uses keywords like
char,int, andfloatto define data types. - Variables can be initialized with values during their declaration.
Data Types
Fundamental Data Types
-
char: Stores a single character, takes up 1 byte of memory. -
int: Stores an integer value, typically takes up 4 bytes of memory. -
float: Stores a single-precision floating-point number, typically takes up 4 bytes of memory.
Derived Data Types
- Based on fundamental data types.
-
short int: Stores an integer value, takes up 2 bytes of memory. -
long int: Stores an integer value, takes up 4 bytes of memory. -
double: Stores a double-precision floating-point number, typically takes up 8 bytes of memory.
C Character I/O
- Use the
%cformat specifier withscanf()to read a single character. - Use the
%cformat specifier withprintf()to display a character. - ASCII values of characters can be displayed using the
%dformat specifier.
C Numeric I/O
- Use the
%dformat specifier withscanf()to read an integer. - Use the
%fformat specifier withscanf()to read a single-precision floating-point number. - Use the
%lfformat specifier withscanf()to read a double-precision floating-point number.
I/O Multiple Values
- Use multiple format specifiers within
scanf()to read multiple values in a single line.
sizeof operator in C
- The
sizeofoperator returns the size of its operand in bytes at compile time. - The result of
sizeofis of the unsigned integral typesize_t. - You can use
sizeofon various data types, including primitives, pointers, and compound types like structures and unions.
Operators in C
- Operators are special symbols used to perform operations on operands.
- Operators are classified based on the number of operands they take.
Unary Operators
- Applied to a single operand.
- Examples: increment (
++), decrement (--),sizeof, type casting.
Binary Operators
- Applied to two operands.
- Examples: Arithmetic Operators, Relational Operators, Shift Operators, Logical Operators, Bitwise Operators, Conditional Operators, Assignment Operator, Misc Operator.
C Arithmetic Operators
- Perform mathematical operations on numerical values.
| Operator | Meaning of Operator |
|---|---|
| + | addition or unary plus |
| - | subtraction or unary minus |
| * | multiplication |
| / | division |
| % | remainder after division (modulo division) |
C Assignment Operators
- Used to assign a value to a variable.
- The most common assignment operator is
=.
| Operator | Example | Same as |
|---|---|---|
| = | a=b | a= b |
| += | a += b | a= a+b |
| -= | a -= b | a= a-b |
| *= | a *= b | a= a*b |
| /= | a /= b | a= a/b |
| %= | a %= b | a= a%b |
C Relational Operators
- Used in decision-making and loops.
| Operator | Meaning of Operator | Example |
|---|---|---|
| == | Equal to | 5 == 3 is evaluated to 0 |
| > | Greater than | 5 > 3 is evaluated to 1 |
| < | Less than | 5 < 3 is evaluated to 0 |
| != | Not equal to | 5 != 3 is evaluated to 1 |
| >= | Greater than or equal to | 5 >= 3 is evaluated to 1 |
| <= | Less than or equal to | 5 <= 3 is evaluated to 0 |
C Bitwise Operators
- Used to perform operations on individual bits of data.
- Examples: AND (
&), OR (|), XOR (^), NOT (~), Left Shift (<<), Right Shift (>>). - Shift operators move bits to the left or right.
- Left shift (
<<) multiplies the value by 2 for each position shifted. - Right shift (
>>) divides the value by 2 for each position shifted.
Loop Constructs
- C loops allow the execution of a sequence of statements multiple times.
- A loop consists of a body and a control statement.
- The control statement checks conditions for the loop's execution.
- Loops in C are used to repeat code execution.
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Description
Explore the fascinating evolution of the C programming language and the UNIX operating system. Discover how C was developed from predecessors like ALGOL and BCPL, and the key figures involved in its standardization. This quiz covers the timeline of significant events in the history of these two foundational technologies.
