1. Character type char:
a byte.
Used to store a small range of integers (-128~127), and "characters" (all ASCII characters, 128).
char a = 97;
char b = 'a'; //'a' character constant
2. Integer type:
4 bytes.
Used to store integers, range: 2 to the 31st power to 2 to the 31st power -1
3, long shape long:
long is long int
used to store integers
On 32-bit systems, 4 bytes, the same as int
On 64-bit systems, 8 bytes
4, long long shape long long:
8 bytes
5, float type (single precision type)
Representation: stored in scientific notation, that is, "mantissa" and "exponent" need to be stored
float x = 1.75E5; // 175000 is 1.75 times and 10 to the 5th power, just save the mantissa 1.75 and the exponent 5.
float y = 1.123456789 //Note here, the precision can only be up to 1.1234568 , and the 7th bit (the integer part is not counted) will be rounded by itself , that is, printf("%f", y);//1.1234568 will be rounded by itself of
Precision: up to 7 significant digits (referring to 7 decimal digits)
6, double type (double precision floating point type)
Used to store data with fractional parts
8 bytes
Precision: up to 16 significant digits (referring to 16 decimal digits)