Mar 2, 2008

Knowing Default Parameters in C++ and Java

C++ allows functions to have default parameters. This is useful when a parameter should have a specified value when the caller does not supply any value.

class DefParam{
    public:

        //Declare the default parameter(s) in function decalaration
        void printVal(int x=10);
};

//Don't repeat the default parameter in function definition
void DefParam::printVal(int val){
    printf("Val = %d\n",val);
}

int main(){
    DefParam obj;
    obj.printVal(); //Passes 10 to printVal()

    obj.printVal(25); //Passes 25 to printVal()
    return 0;
}

$ ./a.exe
Val = 10
Val = 25

Note: Java does not provide default parameter values, but you can use overloading to achieve the same effects.

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