C

Question 1

History of c

Answer 1

-Ritchie and Thompson 1973
Rewrite UNIX kernel with C
-Richie and Kernaghan
Created the “C programming language”

Question 2

C

Answer 2

• general purpose language
• equally usable for applications programming and systems programming (network protocol, database management system, write a compiler)
• ubiquitous (where find C you find UNIX)

Question 3

Features of C

Answer 3

-most toolchains have relatively small footprint
Popular choice for developing embedded systems
Operating systems research and development
Good choice for systems programs that one expects to port

Question 4

Compile time features

Answer 4

• ANSI-compliant compilers provide extensive compile-time diagnostics
• also provide a continuum of optimizations

Question 5

Run time features

Answer 5

-easy to adapt a C compilers output to the execution environment on a platform

Missing features

• no native array bounds checking
• no null pointer checkers
• no uninitialized vars check

Question 6

Aggregate data types

Answer 6

• struct: one mechanism to declare user-defined types
• arrays: can be set scaler or aggregate
• union: similar to structs, but members are overlaid

Question 7

Static and extern

Answer 7

• internal linkage

- external linkage

Question 8

Addresses and pointers

Answer 8

1. All bars refer to data
2. All data resides in memory
3. Every memory location has an address
4. C exposes these details for us to use

Question 9

Program scope

Answer 9

Var exists for programs lifetime and can be accessed from other files (extern)

Question 10

File scope

Answer 10

Visible from its declaration to end of source file

Static

Question 11

Function scope

Answer 11

Visible from begging to end of function

Question 12

Block scope

Answer 12

• visible from form declaration to end of the block

- block is curly brackets

Question 13

C preprocessor

Answer 13

• separate program that runs before the compiler

- allows macro processing, inclusion of additional C source files, conditional compilation

Question 14

Macro processing

Answer 14

• a name that has an associated text string

- macros introduced from #define

Question 15

Standard headers

Answer 15

Stdio.h : standard I/O library funcs 
Math.h : math funcs
Stdlib.h : memory allocation funcs and general utility funcs
string.h : string funcs
ctype.h : char testing and mapping funcs

Question 16

Abstract data type

Answer 16

-an abstract data type is a set of operations which access a collection of stored data

Question 17

FILE *fopen(char *filename, char *mode)

Answer 17

• open file corresponding to filename
• can be r rw or rw+
• if errors occur returns null

Question 18

char *fgets(char *buf, int n, FILE *stream)

Answer 18

• read at most n-1 chars from stream and copy to location buf. Terminates when newline or n-1 chars
• returns null if EOF or error
• set stream to stdin to accept input from standard input

Question 19

int scanf(char *format, […])

Answer 19

• read formatted data from standard input
• returns EOF Shen encountered else returns number of fields successfully converted
• format specifiers encoded in format

Question 20

printf(char *format, […])

Answer 20

• print formatted output to standard output
• returns the number of chars printed
• the format specifiers are encoded in the string format
• takes a variable # of arguments

Question 21

int fprintf(FILE *stream, char *format, […])

Answer 21

-like printf but output goes to already opened stream

Question 22

int fputc(int c, FILE *stream)

Answer 22

• outputs a single char to already opened stream
• character is stored in an int
• num from 0 to 255
• can also pass a char as the first parameter

Question 23

int fclose(FILE *stream)

Answer 23

• closes the stream (flushes all OS buffers such that output file is completed)
• dissociates the actual file from the stream variable
• returns 0 if file closed properly