variables
int led = 13; // implicit var declaration
bool ledState1 = false;
const float pi = 3.14;
#define c1 4 // const declaration
String s = "hello";
N-dimentional arrays
int b[ 2 ][ 2 ] = { { 1, 2 }, { 3, 4 } };
int b[ 2 ][ 2 ];
b[0][0] = 10;// item in array
loops
for(int i=0; i<7; i++)...