Function
Defining a Function
The general form of a C++ function definition is as follows −
return_type function_name( parameter list ) {
body of the function
}
A C++ function definition consists of a function header and a function body. Here are all the parts of a function −
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Return Type − A function may return a value. The return_type is the data type of the value the function returns.
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Some functions perform the desired operations without returning a value. In this case, the return_type is the keyword void.
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Function Name − This is the actual name of the function. The function name and the parameter list together constitute the function signature.
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Parameters − A parameter is like a placeholder. When a function is invoked, you pass a value to the parameter.
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This value is referred to as actual parameter or argument. The parameter list refers to the type, order, and number of the parameters of a function.
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Parameters are optional; that is, a function may contain no parameters.
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Function Body − The function body contains a collection of statements that define what the function does.
Calling a Function
While creating a C++ function, you give a definition of what the function has to do. To use a function, you will have to call or invoke that function.
When a program calls a function, program control is transferred to the called function.
A called function performs defined task and when it’s return statement is executed or when its function-ending closing brace is reached,
it returns program control back to the main program.
To call a function, you simply need to pass the required parameters along with function name, and if function returns a value, then you can store returned value.
For example −
#include <iostream> using namespace std; // function declaration int max(int num1, int num2); int main () { // local variable declaration: int a = 100; int b = 200; int ret; // calling a function to get max value. ret = max(a, b); cout << "Max value is : " << ret << endl; return 0; } // function returning the max between two numbers int max(int num1, int num2) { // local variable declaration int result; if (num1 > num2) result = num1; else result = num2; return result; }
Function Arguments
https://www.tutorialspoint.com/cplusplus/cpp_functions.htm
