Created
July 12, 2012 01:34
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Use of typedefs with struct and enum in C/C++
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| // 1a) Struct declaration and instantiation w/o typedef | |
| struct veg_t{ | |
| int cost; | |
| char c; | |
| }; | |
| struct veg_t potato; | |
| // 1b) or its equivalent with declaration and instantiation combined… | |
| struct veg_t{ | |
| int cost; | |
| char c; | |
| } potato; | |
| // 2a) To avoid having to type the keyword ‘struct’ before every instantiation, typedefs were commonly used as:- | |
| typedef struct fruit_t{ | |
| int cost; | |
| char c; | |
| } fruit_st; | |
| fruit_st apple; | |
| // 2b) This is equivalent to | |
| struct fruit_t{ | |
| int cost; | |
| char c; | |
| }; | |
| typedef struct fruit_t fruit_st; | |
| fruit_st apple; | |
| // 2c) And can also be written as | |
| typedef struct{ | |
| int cost; | |
| char c; | |
| } fruit_t; | |
| fruit_t apple; | |
| /* | |
| Thus, in 1b. the word between } and ; (potato) is the name of the object | |
| while in 2a., it represents the datatype. | |
| In C++, appending the keyword struct is not necessary while instantiating variables thus making the use of typedef redundant. | |
| All of the above also applies to ‘enum’ | |
| */ |
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