Program Structure/Functions
type fnc(type1, ...)
type name:
main() {
declarations
statements
}
type fnc(arg1, ...) {
declarations
statements
return value;
}
/* */ : comment
C Preprocessor
include library file: #include <filename>
include user file: #include "filename"
replacement text: #define name text
Data Types/Declarations
char, int, float, double
Initialization
initialize variable: type name = value
initialize array: type name[]= {value1, ...}
initialize char string: char name[]= "string"
Pointers and Arrays
declare pointer to type : type *name
declare function returning pointer to type : type *f()
declare pointer to function returning type: type (*pf)()
object pointed to by pointer: *pointer
address of object name: &name
array: name[dim]
multi-dim array: name[dim1][dim2]...
Operators
++,--, !, *pointer, &name,
(type) expr, sizeof
*, /, %
+, -
>, >=, <, <=
==, !=
&&
||
+=, -=, *=
Flow of Control
statement terminator: ;
block delimeters: { }
exit from while, do, for: break
next iteration of while, do, for: continue
return value from function: return expr
if (expr) statement
else if (expr) statement
else statement
while(expr)
statement
for (expr1; expr2; expr3)
statement
Input/Output <stdio.h>
print to screen: printf("format", arg1, ...)
read from screen: scanf("format", &name1, ...)
declare file pointer: FILE *fp
open file and attach to pointer fp: fp = fopen("name", "mode")
modes: r (read), w (write), a (append)
close file: fclose(fp)
write to file: fprintf(fp, "format", arg1, ...)
read from file: fscanf(fp, "format", arg1, ...)
Format Codes:
%d integer,
%f float,
%lf double
%15.2f example for float with field width of 15 and 2 digits after decimal
Math Functions <math.h>
sin,cos,tan,sinh,cosh,tanh,exp,log,log10
atan2(y,x), pow(x,y), sqrt, ceil, floor