Detailed syntax of C++ function declaration: from syntax analysis to standard usage analysis

C The function declaration syntax is: returnType functionName(parameterType1 parameterName1, ..., parameterTypeN parameterNameN);, where returnType is the return type, functionName is the function name, parameterType is the parameter type, and parameterName is the parameter name, which must end with a semicolon. .

#Detailed syntax of C function declaration: syntax analysis and usage guide

In C, function declaration is a necessary part of defining a function and is used to specify Function name, parameter list, and return type. It is crucial to master the syntax of function declaration. The following is an analysis of its detailed syntax:

Grammar format

returnType functionName(parameterType1 parameterName1,
                       parameterType2 parameterName2,
                       ...
                       parameterTypeN parameterNameN);

Element	Description
returnType	Specifies the data type returned by the function. Typically a built-in data type such as int or void.
functionName	The name of the function. Follow C identifier naming rules.
parameterType	Specifies the data type of the function parameter. Can have multiple parameters.
parameterName	The name of the parameter. Follow C identifier naming rules.

Practical case

Consider the following example function, which calculates the sum of two numbers and returns the result:

int add(int a, int b) {
    return a + b;
}

In this function declaration , int is the return type, add is the function name, int and int are parameter types, a and b is the parameter name.

Normal usage

• Parameter list: If the function does not accept any parameters, use empty parentheses ().
• Return type: If it is a void function (which does not return any value), the return type can be omitted.
• Parameter type and name: Parameter type and parameter name must be separated by spaces.
• Semicolon: Function declaration must end with a semicolon ;.

Note

• Function declaration does not define the function, it just declares the existence of the function.
• The function definition must be consistent with the function declaration, otherwise it will cause a compilation error.
• C supports function overloading, that is, multiple functions with the same name but different parameter lists.

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