Type Bytes Bits Range
short int 2 16 -16,384 -> +16,383 (16kb)
unsigned short int 2 16 0 -> +32,767 (32Kb)
unsigned int 4 16 0 -> +4,294,967,295 ( 4Gb)
int 4 32 -2,147,483,648 -> +2,147,483,647 ( 2Gb)
long int 4 32 -2,147,483,648 -> +2,147,483,647 ( 2Gb)
signed char 1 8 -128 -> +127
unsigned char 1 8 0 -> +255
float 4 32
double 8 64
long double 12 96

float is number but can take demical part
double the same as float but with more digits.
strings
============
can contain letters,numbers,characters.
"123" is a valid string(always inside quotes)
but it is not a number.
For example You can not add it to a number as it is.
"123" is different from 123