mirror of
https://github.com/LeCoupa/awesome-cheatsheets.git
synced 2026-01-28 22:28:02 -08:00
test
This commit is contained in:
Ajay T Shaju
197
languages/C.md
197
languages/C.md
@@ -1,4 +1,4 @@
|
||||
### main() Function
|
||||
#### main() Function
|
||||
|
||||
* The main() function is the starting point of the program: `int main (int argc, char *argv[])`
|
||||
* The return type of the main() function is an integer (type int) and it is known as the `return value` of the program.
|
||||
@@ -6,13 +6,13 @@
|
||||
|
||||
---
|
||||
|
||||
## Include Files
|
||||
### Include Files
|
||||
|
||||
* The purpose of these files is to tell the compiler about the existence of external functions which the source code will make use of.
|
||||
* The purpose of these files is to tell the compiler about the `existence of external functions which the source code will make use of.`
|
||||
|
||||
---
|
||||
|
||||
## Preprocessor directives:
|
||||
### Preprocessor directives:
|
||||
|
||||
| Directive | Description |
|
||||
|-----------------------------|----------------------------------------------------|
|
||||
@@ -36,7 +36,7 @@
|
||||
|
||||
---
|
||||
|
||||
## Create and execute a program
|
||||
### Create and execute a program
|
||||
|
||||
In Linux systems:
|
||||
|
||||
@@ -46,4 +46,189 @@ In Linux systems:
|
||||
|
||||
3. Write the program and save it
|
||||
|
||||
4. gcc -o nameExecutable nameProgram.c (eg: gcc -o nameProgram_output nameProgram.c)
|
||||
4. gcc -o nameExecutable nameProgram.c (eg: gcc -o nameProgram_output nameProgram.c)
|
||||
|
||||
---
|
||||
|
||||
### Reserved words (32)
|
||||
|
||||
| Term | Description |
|
||||
|------------|------------------------------------------------------------|
|
||||
| `auto` | Optional local declaration |
|
||||
| `break` | Used to exit a loop and used to exit a `switch` statement |
|
||||
| `case` | Choice in a `switch` statement |
|
||||
| `char` | Basic declaration of a type character |
|
||||
| `const` | Prefix declaration meaning the variable cannot be changed |
|
||||
| `continue` | Go to the bottom of a loop in `for`, `while`, and `do` loops |
|
||||
| `default` | Optional last case of a `switch` statement |
|
||||
| `do` | Executable statement, `do-while` loop |
|
||||
| `double` | Basic declaration of double precision floating point |
|
||||
| `else` | Executable statement, part of an "if" structure |
|
||||
| `enum` | Basic declaration of enumeration type |
|
||||
| `extern` | Prefix declaration meaning the variable is defined externally |
|
||||
| `float` | Basic declaration of floating point |
|
||||
| `for` | Executable statement, `for` loop |
|
||||
| `goto` | Jump within a function to a label |
|
||||
| `if` | Executable statement |
|
||||
| `int` | Basic declaration of an integer |
|
||||
| `long` | Prefix declaration applying to many types |
|
||||
| `register` | Prefix declaration meaning to keep a variable in a register |
|
||||
| `return` | Executable statement with or without a value |
|
||||
| `short` | Prefix declaration applying to many types |
|
||||
| `signed` | Prefix declaration applying to some types |
|
||||
| `sizeof` | Operator applying to variables and types, gives size in bytes |
|
||||
| `static` | Prefix declaration to make a local variable static |
|
||||
| `struct` | Declaration of a structure, like a record |
|
||||
| `switch` | Executable statement for cases |
|
||||
| `typedef` | Creates a new type name for an existing type |
|
||||
| `union` | Declaration of variables that share the same memory locations |
|
||||
| `unsigned` | Prefix declaration applying to some types |
|
||||
| `void` | Declaration of a typeless variable |
|
||||
| `volatile` | Prefix declaration meaning the variable can be changed at any time |
|
||||
| `while` | Executable statement, `while` loop or `do-while` loop |
|
||||
|
||||
---
|
||||
|
||||
### Basic types
|
||||
|
||||
| Type | Description |
|
||||
|---------|--------------------------------------------------------|
|
||||
| `char` | Character type, usually one byte (a string is an array of `char`) |
|
||||
| `int` | Integer type, usually 2 or 4 bytes (default) |
|
||||
| `float` | Floating-point type, usually 4 bytes |
|
||||
| `double`| Floating-point type, usually 8 bytes |
|
||||
| `void` | No type, typeless |
|
||||
| `enum` | Enumeration type (user defines the type name) |
|
||||
|
||||
---
|
||||
|
||||
### Type modifiers, prefix for basic types
|
||||
|
||||
| Modifier | Description |
|
||||
|------------|--------------------------------------------------------|
|
||||
| `signed` | Has a sign (default) |
|
||||
| `unsigned` | No sign bit in the variable |
|
||||
| `long` | Longer version of a type (e.g., `long int`) |
|
||||
| `short` | Shorter version of a type (e.g., `short int`) |
|
||||
| `const` | Variable cannot be modified or stored into |
|
||||
|
||||
---
|
||||
|
||||
### Storage Types
|
||||
|
||||
| Prefix | Description |
|
||||
|-----------|-------------------------------------------------------|
|
||||
| `auto` | Local variable (default) |
|
||||
| `static` | Permanent, exists beyond function scope (not `auto`) |
|
||||
| `volatile`| Can change from external influences |
|
||||
| `extern` | Variables are defined elsewhere, externally |
|
||||
| `register`| Suggests that the variable should be stored in a register if possible |
|
||||
|
||||
---
|
||||
### Operators
|
||||
|
||||
| Operator | Description |
|
||||
|----------|----------------------------------------------------|
|
||||
| `( )` | Grouping parenthesis, function call |
|
||||
| `[ ]` | Array indexing, also `[ ][ ]` etc. |
|
||||
| `->` | Selector, structure pointer |
|
||||
| `.` | Select structure element |
|
||||
| `!` | Relational not, complement, `!a` yields true or false |
|
||||
| `~` | Bitwise not, ones complement, `~a` |
|
||||
| `++` | Increment, pre or post to a variable |
|
||||
| `--` | Decrement, pre or post to a variable |
|
||||
| `-` | Unary minus, `-a` |
|
||||
| `+` | Unary plus, `+a` |
|
||||
| `*` | Indirect, the value of a pointer, `*p` is the value at pointer `p` address |
|
||||
| `&` | The memory address, `&b` is the memory address of variable `b` |
|
||||
| `sizeof` | Size in bytes, `sizeof a` or `sizeof (int)` |
|
||||
| `(type)` | Cast, explicit type conversion, `(float)i`, `(*fun)(a, b)`, `(int*)x` |
|
||||
| `*` | Multiply, `a * b` |
|
||||
| `/` | Divide, `a / b` |
|
||||
| `%` | Modulo, `a % b` |
|
||||
| `+` | Add, `a + b` |
|
||||
| `-` | Subtract, `a - b` |
|
||||
| `<<` | Shift left, left operand is shifted left by right operand bits |
|
||||
| `>>` | Shift right, left operand is shifted right by right operand bits |
|
||||
| `<` | Less than, result is true or false, `a < b` |
|
||||
| `<=` | Less than or equal, result is true or false, `a <= b` |
|
||||
| `>` | Greater than, result is true or false, `a > b` |
|
||||
| `>=` | Greater than or equal, result is true or false, `a >= b` |
|
||||
| `==` | Equal, result is true or false, `a == b` |
|
||||
| `!=` | Not equal, result is true or false, `a != b` |
|
||||
| `&` | Bitwise and, `a & b` |
|
||||
| `^` | Bitwise exclusive or, `a ^ b` |
|
||||
| | | Bitwise or, `a | b` |
|
||||
| `&&` | Relational and, result is true or false, `a < b && c >= d` |
|
||||
| | | | Relational or, result is true or false, `a < b || c >= d` |
|
||||
| `?` | Ternary conditional, `exp1 ? exp2 : exp3`, result is `exp2` if `exp1` is not 0, else result is `exp3` |
|
||||
| `=` | Store |
|
||||
| `+=` | Add and store |
|
||||
| `-=` | Subtract and store |
|
||||
| `*=` | Multiply and store |
|
||||
| `/=` | Divide and store |
|
||||
| `%=` | Modulo and store |
|
||||
| `<<=` | Shift left and store |
|
||||
| `>>=` | Shift right and store |
|
||||
| `&=` | Bitwise and and store |
|
||||
| `^=` | Bitwise exclusive or and store |
|
||||
| | = | Bitwise or and store |
|
||||
| `,` | Separator, as in `(y = x, z = ++x)` |
|
||||
|
||||
---
|
||||
### Operator precedence
|
||||
|
||||
#### More precedence
|
||||
|
||||
| Associativity | Operators |
|
||||
|---------------|---------------------------------------------------|
|
||||
| LR | `( )`, `[ ]`, `->`, `.`, `x++`, `x--` |
|
||||
| RL | `!`, `~`, `-`, `+`, `++x`, `--x`, `*`, `&`, `sizeof (type)` |
|
||||
| LR | `*`, `/`, `%` |
|
||||
| LR | `+`, `-` |
|
||||
| LR | `<<`, `>>` |
|
||||
| LR | `<`, `<=`, `>`, `>=` |
|
||||
| LR | `==`, `!=` |
|
||||
| LR | `&` |
|
||||
| LR | `^` |
|
||||
| LR | `|` |
|
||||
| LR | `&&` |
|
||||
| LR | `||` |
|
||||
| RL | `? :` |
|
||||
| RL | `=`, `+=`, `-=` ,`*=`, `/=`, `%=`, `>>=`, `<<=`, `&=`, `^=`, `|=` |
|
||||
| LR | `,` |
|
||||
|
||||
|
||||
#### Less precedence
|
||||
|
||||
|
||||
---
|
||||
### Conditional Branching
|
||||
|
||||
if ( condition ) statement ;
|
||||
else statement_2 ; /* optional else clause */
|
||||
|
||||
---
|
||||
|
||||
### Switch statement
|
||||
|
||||
switch ( expression ) /* constants must be unique */
|
||||
{
|
||||
case constant_1: /* do nothing for this case */
|
||||
break;
|
||||
case constant_2: /* drop through and do same constant_3 */
|
||||
case constant_3:
|
||||
statement_sequence /* can have but does not need { } */
|
||||
break;
|
||||
case constant_4:
|
||||
statement_sequence /* does this and next statement_sequence also*/
|
||||
case constant_5:
|
||||
statement_sequence
|
||||
break;
|
||||
default: /* default executes if no constant equals*/
|
||||
statement_sequence /* the expression. This is optional */
|
||||
}
|
||||
|
||||
---
|
||||
|
||||
---
|
||||
Reference in New Issue
Block a user