summaryrefslogtreecommitdiffhomepage
path: root/c.html.markdown
diff options
context:
space:
mode:
authorevuez <helloevuez@gmail.com>2015-10-16 10:42:41 +0200
committerevuez <helloevuez@gmail.com>2015-10-16 10:42:41 +0200
commit85adff2c39e6eae77a915638961f2144ef18b5c9 (patch)
treead87847bd5cca361b2e4582a361c4d4d70948aec /c.html.markdown
parent375f0c18ae9b8d8732c480d0647becf1e82adf3e (diff)
parent25e49b8cf10d3879431eae6ffe8a8e5f88843b8d (diff)
Merge 'master' of github.com:adambard/learnxinyminutes-docs
Diffstat (limited to 'c.html.markdown')
-rw-r--r--c.html.markdown61
1 files changed, 58 insertions, 3 deletions
diff --git a/c.html.markdown b/c.html.markdown
index 3339032f..a8f71057 100644
--- a/c.html.markdown
+++ b/c.html.markdown
@@ -6,8 +6,8 @@ contributors:
- ["Árpád Goretity", "http://twitter.com/H2CO3_iOS"]
- ["Jakub Trzebiatowski", "http://cbs.stgn.pl"]
- ["Marco Scannadinari", "https://marcoms.github.io"]
+ - ["Zachary Ferguson", "https://github.io/zfergus2"]
- ["himanshu", "https://github.com/himanshu81494"]
-
---
Ah, C. Still **the** language of modern high-performance computing.
@@ -54,6 +54,8 @@ int function_2(void);
// Must declare a 'function prototype' before main() when functions occur after
// your main() function.
int add_two_ints(int x1, int x2); // function prototype
+// although `int add_two_ints(int, int);` is also valid (no need to name the args),
+// it is recommended to name arguments in the prototype as well for easier inspection
// Your program's entry point is a function called
// main with an integer return type.
@@ -74,6 +76,9 @@ int main (int argc, char** argv)
///////////////////////////////////////
// Types
///////////////////////////////////////
+
+ // All variables MUST be declared at the top of the current block scope
+ // we declare them dynamically along the code for the sake of the tutorial
// ints are usually 4 bytes
int x_int = 0;
@@ -232,7 +237,7 @@ int main (int argc, char** argv)
0 || 1; // => 1 (Logical or)
0 || 0; // => 0
- // Conditional expression ( ? : )
+ // Conditional ternary expression ( ? : )
int e = 5;
int f = 10;
int z;
@@ -302,6 +307,8 @@ int main (int argc, char** argv)
for (i = 0; i <= 5; i++) {
; // use semicolon to act as the body (null statement)
}
+ // Or
+ for (i = 0; i <= 5; i++);
// branching with multiple choices: switch()
switch (a) {
@@ -678,8 +685,56 @@ typedef void (*my_fnp_type)(char *);
// , | left to right //
//---------------------------------------------------//
-```
+/******************************* Header Files **********************************
+
+Header files are an important part of c as they allow for the connection of c
+source files and can simplify code and definitions by seperating them into
+seperate files.
+
+Header files are syntaxtically similar to c source files but reside in ".h"
+files. They can be included in your c source file by using the precompiler
+command #include "example.h", given that example.h exists in the same directory
+as the c file.
+*/
+
+/* A safe guard to prevent the header from being defined too many times. This */
+/* happens in the case of circle dependency, the contents of the header is */
+/* already defined. */
+#ifndef EXAMPLE_H /* if EXAMPLE_H is not yet defined. */
+#define EXAMPLE_H /* Define the macro EXAMPLE_H. */
+
+/* Other headers can be included in headers and therefore transitively */
+/* included into files that include this header. */
+#include <string.h>
+/* Like c source files macros can be defined in headers and used in files */
+/* that include this header file. */
+#define EXAMPLE_NAME "Dennis Ritchie"
+/* Function macros can also be defined. */
+#define ADD(a, b) (a + b)
+
+/* Structs and typedefs can be used for consistency between files. */
+typedef struct node
+{
+ int val;
+ struct node *next;
+} Node;
+
+/* So can enumerations. */
+enum traffic_light_state {GREEN, YELLOW, RED};
+
+/* Function prototypes can also be defined here for use in multiple files, */
+/* but it is bad practice to define the function in the header. Definitions */
+/* should instead be put in a c file. */
+Node createLinkedList(int *vals, int len);
+
+/* Beyond the above elements, other definitions should be left to a c source */
+/* file. Excessive includeds or definitions should, also not be contained in */
+/* a header file but instead put into separate headers or a c file. */
+
+#endif /* End of the if precompiler directive. */
+
+```
## Further Reading
Best to find yourself a copy of [K&R, aka "The C Programming Language"](https://en.wikipedia.org/wiki/The_C_Programming_Language)