IOS--DAY01---data types

Data types---Basic data types, constructed types, pointer types

Basic data Types-integer, float, character, enum type

Constructed type---array type, struct type, common type

Pointer type

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Boolean type:

The lower level of OC is actually using signed char to represent BOOL, while the bottom of the Yes,no two value is actually 1 and 0;

A non-zero integer assigned to a variable of type bool may not be yes! If 256 is converted to binary 100000000 at the bottom, this will get no

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Expression type auto-promotion

When an arithmetic expression contains values of more than one base type, the data type of the entire arithmetic expression will automatically ascend.

The data types are from low to high levels, respectively:

Short---int---long---long long---float----double---long double

Short s=5;

NSLog (@ "%ld", sizeof (s-2));

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IOS--DAY01---data types