Integer is similar to the INT type in C language, that is, the integer type in mathematics, and has no decimal point. It takes up 8 bytes.
Real numbers are similar to floating-point numbers in C language, that is, real numbers in mathematics, and real numbers contain integer types, but most of the bytes it occupies are 16 bytes.
String is a character type in C language, that is, all our Chinese characters, English and other input and output are character types.