diff options
| -rw-r--r-- | c.html.markdown | 43 |
1 files changed, 15 insertions, 28 deletions
diff --git a/c.html.markdown b/c.html.markdown index f4edfca5..4187d757 100644 --- a/c.html.markdown +++ b/c.html.markdown @@ -20,7 +20,7 @@ memory management and C will take you as far as you need to go. Multi-line comments look like this. They work in C89 as well. */ -// Constants: #define <keyword> (no semicolon at end) +// Constants: #define <keyword> #define DAYS_IN_YEAR 365 //enumeration constants are also ways to declare constants. @@ -38,7 +38,7 @@ enum days {SUN = 1, MON, TUE, WED, THU, FRI, SAT}; // Declare function signatures in advance in a .h file, or at the top of // your .c file. -void function_1(char s[]); +void function_1(char c); int function_2(void); // Must declare a 'function prototype' before main() when functions occur after @@ -84,8 +84,8 @@ int main() { unsigned long long ux_long_long; // chars inside single quotes are integers in machine's character set. - '0' //==> 48 on the ASCII character set. - 'A' //==> 65 on the ASCII character set. + '0' // => 48 in the ASCII character set. + 'A' // => 65 in the ASCII character set. // sizeof(T) gives you the size of a variable with type T in bytes // sizeof(obj) yields the size of the expression (variable, literal, etc.). @@ -154,16 +154,16 @@ int main() { {6, 7, 8, 9, 0} } //access elements: - int array_int = multi_array[0][2]; //=> 3 + int array_int = multi_array[0][2]; // => 3 /////////////////////////////////////// // Operators /////////////////////////////////////// - int i1 = 1, i2 = 2; // Shorthand for multiple declaration + // Shorthands for multiple declarations: + int i1 = 1, i2 = 2; float f1 = 1.0, f2 = 2.0; - //more shorthands: int a, b, c; a = b = c = 0; @@ -215,9 +215,9 @@ int main() { //Increment and decrement operators: char *s = "iLoveC" int j = 0; - s[j++]; // => "i" Returns value of j to s THEN increments value of j. + s[j++]; // => "i". Returns the j-th item of s THEN increments value of j. j = 0; - s[++j]; // => "L" Increments value of j THEN returns value of j to s. + s[++j]; // => "L". Increments value of j THEN returns j-th value of s. // same with j-- and --j // Bitwise operators! @@ -271,7 +271,7 @@ int main() { printf("\n"); // *****NOTES*****: - // Loops MUST always have a body. If no body is needed, do: + // Loops and Functions MUST have a body. If no body is needed: int i; for (i = 0; i <= 5; i++) { ; // use semicolon to act as the body (null statement) @@ -429,12 +429,12 @@ int add_two_ints(int x1, int x2) } /* -Functions are call by value. So when a function is called, the arguments passed -to the function are copies of original arguments (except arrays). Anything you -do to your arguments do not change the value of the actual argument where the -function was called. +Functions are call by value. When a function is called, the arguments passed to +the function are copies of the original arguments (except arrays). Anything you +do to the arguments in the function do not change the value of the original +argument where the function was called. -You can use pointers if you need to edit the original argument values. +Use pointers if you need to edit the original argument values. Example: in-place string reversal */ @@ -452,19 +452,6 @@ void str_reverse(char *str_in) } } -///////////////////////////////////// -// Built in functions: -///////////////////////////////////// -// from: #include <stdio.h> -// ** getchar() ** -// int c = getchar(); //reads character from input. -// If input = hi, 'h' is returned then next call, 'i' returned. -while ((c = getchar()) != EOF) { // EOF constant "end of file". - // Linux: CTRL+D, Windows: CTRL+X - // must have () around getchar() as != is run before =. - putchar(c); //prints character (without newline at end) -} - //if referring to external variables outside function, must use extern keyword. int i = 0; void testFunc() { |