C Vars

• Declare using:
  • {dataType} {varName}
• Can assign by using "=" followed by a value
• "#define" creates a text substitution (no type, just replaces raw txt):

#include <stdio.h> 
// Defining macros with constant value 
#define PI 3.14159265359 

int main() 
{ 

    int radius = 21; 
    int area; 

    // Using macros to calculate area of circle 
    area = PI * radius * radius; 

    printf("Area of Circle of radius %d: %d", radius, area); 

    return 0; 
}

• const creates a constant:
  • const int Thing = 4;
  • //can't be changed
  • //naming conventions use capital letters to start const name

Data Type	Size (bytes)	Format Specifier
short	2	%hd
unsigned short	2	%hu
unsigned int	4	%u
int	4	%d
long int	4	%ld
unsigned long int	4	%lu
long long	8	%lld
unsigned long long	8	%llu
signed char	1	%c
unsigned char	1	%c
float	4	%f
double	8	%lf
long double	16	%Lf
String	custom	%s
Buffer/Strings:

• To create a string, use [] after the name to specify byte amounts
  • char name[25]
  • //"name" only takes up 25 bytes, can't store more
  • //Not specifying an amount just lets it have any amt
    Arrays:
• To find Size of array, use sizeof in a weird way
  • int size sizeof(array)/sizeof(array[0])
• Collection of elements OF SAME TYPE
  • `{arrayType} {name}[] = {el1, el2, etc}
  • double prices[] = {5.0, 2.0, 3.0}
• Note that strings are arrays of chars.
• For an array of strings, simply use another set of []
  • char cars[][10] = {"mercedes", "ford"}
  • //Note that 10 is the max size of EACH ELEMENT, not total
  • To change an element by index, use strcpy():
    • strcpy({array}, "{newVal"})