Functions as arguments

This is a discussion on Functions as arguments within the C++ Programming forums, part of the General Programming Boards category; Is there a way to have functions as arguments? If I have a function that takes a double and returns ...

  1. #1
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    Functions as arguments

    Is there a way to have functions as arguments? If I have a function that takes a double and returns a double, is there a way I can make another function that takes the first function as an argument?

  2. #2
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    Code:
    int foo();
    
    int foofoo(int var);
    
    int main()
    {
        int a = foofoo(foo());
        return 0;
    }
    like that?

  3. #3
    C++ Witch laserlight's Avatar
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    Yes, for example:
    Code:
    #include <iostream>
    
    double foo(double x);
    
    void bar(double (*func)(double), double x);
    
    int main()
    {
        bar(foo, 1.5);
    }
    
    double foo(double x)
    {
        return x + x;
    }
    
    void bar(double (*func)(double), double x)
    {
        std::cout << func(x) << std::endl;
    }
    So func in bar is a function pointer, in this case a function pointer to foo. You could also use function objects instead, which can be more powerful.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

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