iskm/learnxinyminutes-docs
1
0
Fork 0
mirror of https://github.com/adambard/learnxinyminutes-docs.git synced 2024-12-23 17:41:41 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

main() -> main(void) & fix spacing in c.html.markdown

Browse Source
This commit is contained in:
Joe Savage 2015-08-29 11:58:03 +01:00
parent 85d80b9e5d
commit 7cb94b3b85
1 changed files with 12 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
c.html.markdown
View File

@ -18,9 +18,9 @@ memory management and C will take you as far as you need to go.
```c ```c
// Single-line comments start with // - only available in C99 and later. // Single-line comments start with // - only available in C99 and later.
/* /*
Multi-line comments look like this. They work in C89 as well. Multi-line comments look like this. They work in C89 as well.
*/ */
/* /*
Multi-line comments don't nest /* Be careful */ // comment ends on this line... Multi-line comments don't nest /* Be careful */ // comment ends on this line...
@ -55,7 +55,7 @@ int add_two_ints(int x1, int x2); // function prototype
// Your program's entry point is a function called // Your program's entry point is a function called
// main with an integer return type. // main with an integer return type.
int main() { int main(void) {
// print output using printf, for "print formatted" // print output using printf, for "print formatted"
// %d is an integer, \n is a newline // %d is an integer, \n is a newline
printf("%d\n", 0); // => Prints 0 printf("%d\n", 0); // => Prints 0
@ -157,12 +157,12 @@ int main() {
int cha = 'a'; // fine int cha = 'a'; // fine
char chb = 'a'; // fine too (implicit conversion from int to char) char chb = 'a'; // fine too (implicit conversion from int to char)
//Multi-dimensional arrays: // Multi-dimensional arrays:
int multi_array[2][5] = { int multi_array[2][5] = {
{1, 2, 3, 4, 5}, {1, 2, 3, 4, 5},
{6, 7, 8, 9, 0} {6, 7, 8, 9, 0}
}; };
//access elements: // access elements:
int array_int = multi_array[0][2]; // => 3 int array_int = multi_array[0][2]; // => 3
/////////////////////////////////////// ///////////////////////////////////////
@ -219,13 +219,13 @@ int main() {
0 || 1; // => 1 (Logical or) 0 || 1; // => 1 (Logical or)
0 || 0; // => 0 0 || 0; // => 0
//Conditional expression ( ? : ) // Conditional expression ( ? : )
int e = 5; int e = 5;
int f = 10; int f = 10;
int z; int z;
z = (e > f) ? e : f; // => 10 "if e > f return e, else return f." z = (e > f) ? e : f; // => 10 "if e > f return e, else return f."
//Increment and decrement operators: // Increment and decrement operators:
char *s = "iLoveC"; char *s = "iLoveC";
int j = 0; int j = 0;
s[j++]; // => "i". Returns the j-th item of s THEN increments value of j. s[j++]; // => "i". Returns the j-th item of s THEN increments value of j.
@ -371,7 +371,7 @@ int main() {
x_array[xx] = 20 - xx; x_array[xx] = 20 - xx;
} // Initialize x_array to 20, 19, 18,... 2, 1 } // Initialize x_array to 20, 19, 18,... 2, 1
// Declare a pointer of type int and initialize it to point to x_array // Declare a pointer of type int and initialize it to point to x_array
int* x_ptr = x_array; int* x_ptr = x_array;
// x_ptr now points to the first element in the array (the integer 20). // x_ptr now points to the first element in the array (the integer 20).
// This works because arrays often decay into pointers to their first element. // This works because arrays often decay into pointers to their first element.
@ -404,8 +404,8 @@ int main() {
*(my_ptr + xx) = 20 - xx; // my_ptr[xx] = 20-xx *(my_ptr + xx) = 20 - xx; // my_ptr[xx] = 20-xx
} // Initialize memory to 20, 19, 18, 17... 2, 1 (as ints) } // Initialize memory to 20, 19, 18, 17... 2, 1 (as ints)
// Dereferencing memory that you haven't allocated gives // Dereferencing memory that you haven't allocated gives
// "unpredictable results" - the program is said to invoke "undefined behavior" // "unpredictable results" - the program is said to invoke "undefined behavior"
printf("%d\n", *(my_ptr + 21)); // => Prints who-knows-what? It may even crash. printf("%d\n", *(my_ptr + 21)); // => Prints who-knows-what? It may even crash.
// When you're done with a malloc'd block of memory, you need to free it, // When you're done with a malloc'd block of memory, you need to free it,
@ -471,13 +471,13 @@ str_reverse(c);
printf("%s\n", c); // => ".tset a si sihT" printf("%s\n", c); // => ".tset a si sihT"
*/ */
//if referring to external variables outside function, must use extern keyword. // if referring to external variables outside function, must use extern keyword.
int i = 0; int i = 0;
void testFunc() { void testFunc() {
extern int i; //i here is now using external variable i extern int i; //i here is now using external variable i
} }
//make external variables private to source file with static: // make external variables private to source file with static:
static int j = 0; //other files using testFunc2() cannot access variable j static int j = 0; //other files using testFunc2() cannot access variable j
void testFunc2() { void testFunc2() {
extern int j; extern int j;