Data types

In C, data can be defined in 3 types. They are int, char, double or float.

int is integers, which is numbers with no decimal point.
char hold a maximum value of 255. Usually used to store characters in arrays.
float or double store values with decimal point.

Now, these values data types can be positive or negative. Example:-

unsigned int counter;

So now counter is a non negative integer value. If you want the variable counter to be able to store negative values, it would be defined as:-

signed int counter;

There is a limit to the value counter can hold. Below is the table for your reference of the maximum and minimum data type values.

Type	Size in bytes	Range
(unsigned) char	1	0 .. 255
signed char	1	- 128 .. 127
(signed) short (int)	1	- 128 .. 127
unsigned short (int)	1	0 .. 255
(signed) int	2	-32768 .. 32767
unsigned (int)	2	0 .. 65535
(signed) long (int)	4	-2147483648 .. 2147483647
unsigned long (int)	4	0 .. 4294967295
float	4	±1.17549435082 * 10-38 .. ±6.80564774407 * 1038
double	4	±1.17549435082 * 10-38 .. ±6.80564774407 * 1038
long double	4	±1.17549435082 * 10-38 .. ±6.80564774407 * 1038

So use the right data types and save memory. I will explain long and short in a later post.