记录几种常用语言的语法,方便写作 #C #include int add (int, int); int subtract (int, int); int do_math (int (*math_fn_ptr) (int, int), int, int); int main();

int main()
{
  int result;

  result = do_math (add, 10, 5);
  printf ("Addition = %d.\n", result);

  result = do_math (subtract, 40, 5);
  printf ("Subtraction = %d.\n\n", result);

  return 0;
}

int add (int num1, int num2)
{
  return (num1 + num2);
}


int subtract (int num1, int num2)
{
  return (num1 - num2);
}


int do_math (int (*math_fn_ptr) (int, int), int num1, int num2)
{
  int result;

  printf ("\ndo_math here.\n");

  /* Call one of the math functions passed to us:
     either add or subtract. */

  result = (*math_fn_ptr) (num1, num2);
  return result;
} #C++
#include <iostream>
using namespace std;

class CRectangle {
    int width, height;
  public:
    void set_values (int, int);
    int area (void) {return (width * height);}
};

void CRectangle::set_values (int a, int b) {
  width = a;
  height = b;
}

int main () {
  CRectangle a, *b, *c;
  CRectangle * d = new CRectangle[2];
  b= new CRectangle;
  c= &a;
  a.set_values (1,2);
  b->set_values (3,4);
  d->set_values (5,6);
  d[1].set_values (7,8);
  cout << "a area: " << a.area() << endl;
  cout << "*b area: " << b->area() << endl;
  cout << "*c area: " << c->area() << endl;
  cout << "d[0] area: " << d[0].area() << endl;
  cout << "d[1] area: " << d[1].area() << endl;
  delete[] d;
  delete b;
  return 0;
}

Objective-c

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