Constants in C language are generally divided into integer constants and floating-point constants.

The default data type of integer constants is int, that is, signed integers.

The default type of floating-point constants is double type, that is, long floating-point type.

Note: There is a special integer constant, that is, the character constant, which leads to the string constant. The default type of character constants is char type, that is, signed character type and string constant type, generally const int type. At the same time, different compilers are slightly different, but generally follow this rule.