C language data types may be converted:
1) cast
2) implicit type conversion
Cast syntax:
- (Type) var_name; the variable name
- (Type) value; variable value
Forced conversion result type:
- the target type can accommodate target: the results unchanged
- the target type can not accommodate target: the target will generate truncated.
note:
Not all of the cast can succeed, when it is not mandatory conversion, the compiler will generate an error message.
On 32-bit machines, the address of the global variable occupies four bytes.
Implicit type conversions: active typecast compiler.
(In engineering development, some compiler bug is caused by an active implicit type conversions.)
note:
Type low-to-high type implicit conversion is safe, no truncation;
High-low type to the type of implicit conversion is unsafe, it can lead to incorrect results.
Implicit type conversion occurred points:
1) arithmetic formula, a low to a high conversion type type;
2) assignment expression, the value is converted to an expression of the type variable on the left;
3) The function is called argument conversion parameter type;
4) function returns the value, return type of the return value is converted to an expression;
summary:
