C language is not a strict subset of C + +

is C language a subset of C + +? is C + + extensible and contains all C language content on the basis of C?

Reply:

From a practical point of view, C + + belongs to a superset of C language, which is basically compatible with ANSI C. However, some features of c are not supported in C + + from a compilation perspective. In contrast, ANSI C inherits several features of C + +, including prototypes and constants. Therefore, these two languages are not another superset or subset, and they differ in the definition of some common constructs. Despite these differences, many C programs can be compiled in the C + + environment, and many of the latest compilers provide both C and C + + compilation modes. However, do not compile the C code completely as C + + code, or you will get an error when encountering an incompatibility problem.

C + + has been improved as follows.

The C + + array definition is limited. In the C language, the array is initialized without count the group overflow judgment, which makes it easier for the array not to have enough space to hold the data and produce an error. C + + has made some improvements, and expressions like char str[3]= "Jim" are considered to be a mistake, but it is legal in the C language.

In C + +, declarative statements can be interspersed between statements. As you know, in C, all declarations in a block of statements must precede all statements, and C + + removes this restriction so that declaration statements can be interspersed between statements.

C + + is the most important improvement on the object-oriented expansion. C language is a process-oriented structured language, and C + + is an object-oriented language, it adds the object-oriented mechanism on the basis of C language, which makes C + + more perfect and practical than C language.

There are limitations in C + + that do not exist in the language.

In C + +, user code cannot call the main function main () function, but in c it is possible (but rarely).

The declaration of a function prototype in C + + is strict, the requirement must be complete, and in C language is not so strict.

In C + +, the name of a type defined by a TypeDef cannot conflict with an existing structure name, but it is allowed in C language.

C + + prescribes stricter type handling, for example, when the void* pointer is assigned to another type of pointer, C + + requires mandatory type conversion, which is not necessary in C.

C + + has different meanings in C language:

C + + has expanded the keywords in the language, adding at least more than 10. These keywords can be used as identifiers in the C language, but if such C-language code is compiled using the C + + compiler, an error message is generated.

In C + +, the structure name of the inner scope hides the same object name in outer space, which is not the case in the C language.

In C + +, annotations can use the "//" notation, which is not available in the C language.

Comments

In general, C is the predecessor of C + +, which describes only part of the difference. As can be seen from the above, C + + does not have some of the most basic problems in C language to improve, it still retains the C language of many flaws, and on this basis, and piled up a lot of complex things. However, despite a number of shortcomings, C and C + + are widely used, which also shows the value of its existence.

There are many differences between C and C + +, and it is necessary to analyze the difference between the two by actual programming, and to stay alert and avoid mistakes when using each other.

---references: http://book.51cto.com/art/201203/326393.htm

C language is not a strict subset of C + +