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authorIan Bertolacci <ian.bertolacci@gmail.com>2015-10-02 10:15:08 -0600
committerIan Bertolacci <ian.bertolacci@gmail.com>2015-10-02 10:15:08 -0600
commit53790a00980f0ab58efeea5a20c97366daeca401 (patch)
tree60cced8d7b62becacd31b6fb56d9a7c41f1de809 /c.html.markdown
parent938720074b8b18a9ada93fb8a040b9ca1a813747 (diff)
parentd5b5b19ca909b573d0b0623604f1ff9369ab04ff (diff)
Merge branch 'master' of github.com:adambard/learnxinyminutes-docs
Diffstat (limited to 'c.html.markdown')
-rw-r--r--c.html.markdown30
1 files changed, 15 insertions, 15 deletions
diff --git a/c.html.markdown b/c.html.markdown
index d3f20eda..8e631de4 100644
--- a/c.html.markdown
+++ b/c.html.markdown
@@ -18,9 +18,9 @@ memory management and C will take you as far as you need to go.
```c
// 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 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
// main with an integer return type.
-int main() {
+int main(void) {
// print output using printf, for "print formatted"
// %d is an integer, \n is a newline
printf("%d\n", 0); // => Prints 0
@@ -157,12 +157,12 @@ int main() {
int cha = 'a'; // fine
char chb = 'a'; // fine too (implicit conversion from int to char)
- //Multi-dimensional arrays:
+ // Multi-dimensional arrays:
int multi_array[2][5] = {
{1, 2, 3, 4, 5},
{6, 7, 8, 9, 0}
};
- //access elements:
+ // access elements:
int array_int = multi_array[0][2]; // => 3
///////////////////////////////////////
@@ -183,8 +183,8 @@ int main() {
i1 / i2; // => 0 (0.5, but truncated towards 0)
// You need to cast at least one integer to float to get a floating-point result
- (float)i1 / i2 // => 0.5f
- i1 / (double)i2 // => 0.5 // Same with double
+ (float)i1 / i2; // => 0.5f
+ i1 / (double)i2; // => 0.5 // Same with double
f1 / f2; // => 0.5, plus or minus epsilon
// Floating-point numbers and calculations are not exact
@@ -219,13 +219,13 @@ int main() {
0 || 1; // => 1 (Logical or)
0 || 0; // => 0
- //Conditional expression ( ? : )
+ // Conditional expression ( ? : )
int e = 5;
int f = 10;
int z;
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";
int j = 0;
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;
} // 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;
// 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.
@@ -404,8 +404,8 @@ int main() {
*(my_ptr + xx) = 20 - xx; // my_ptr[xx] = 20-xx
} // Initialize memory to 20, 19, 18, 17... 2, 1 (as ints)
- // Dereferencing memory that you haven't allocated gives
- // "unpredictable results" - the program is said to invoke "undefined behavior"
+ // Dereferencing memory that you haven't allocated gives
+ // "unpredictable results" - the program is said to invoke "undefined behavior"
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,
@@ -471,13 +471,13 @@ str_reverse(c);
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;
void testFunc() {
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
void testFunc2() {
extern int j;
@@ -634,7 +634,7 @@ Best to find yourself a copy of [K&R, aka "The C Programming Language"](https://
It is *the* book about C, written by Dennis Ritchie, the creator of C, and Brian Kernighan. Be careful, though - it's ancient and it contains some
inaccuracies (well, ideas that are not considered good anymore) or now-changed practices.
-Another good resource is [Learn C the hard way](http://c.learncodethehardway.org/book/).
+Another good resource is [Learn C The Hard Way](http://c.learncodethehardway.org/book/).
If you have a question, read the [compl.lang.c Frequently Asked Questions](http://c-faq.com).