fork download 
  1. #include <iostream>
  2. #include <cstdlib>
  3. #include <ctime>
  4. using namespace std;
  5.  
  6. typedef int (*FUNC)(int, int);
  7. typedef int (*CALL)(FUNC, int, int);
  8.  
  9. int add(int, int);
  10. int mul(int, int);
  11.  
  12. int call1(int (*)(int, int), int, int); // 関数ポインタそのまま
  13. int call2(FUNC, int, int);              // typedefすると簡潔に書ける
  14.  
  15. int callcallA(CALL, FUNC, int, int);     // 大量の関数ポインタの引数があっても簡潔に書ける！
  16.  
  17. // 真面目に書くと？　カオスの極み
  18. int callcallB(int (*)(int (*)(int, int), int, int), int (*)(int, int), int, int);
  19.  
  20. int main() {
  21.  
  22. 	int (*f)(int,int);  // 関数ポインタそのまま
  23. 	FUNC g;             // typedefすると簡潔に書ける
  24.  
  25. 	srand((unsigned int)time(NULL));
  26.  
  27. 	if (rand() & 1) {
  28. 		f = add;
  29. 		g = add;
  30. 	} else {
  31. 		f = mul;
  32. 		g = mul;
  33. 	}
  34. 	cout << (*f)(111, 9) << endl;
  35. 	cout << (*g)(111, 9) << endl;
  36.  
  37. 	cout << call1(add, 10, 203) << endl;
  38. 	cout << call1(mul, 10, 203) << endl;
  39.  
  40. 	cout << call2(add, 10, 203) << endl;
  41. 	cout << call2(mul, 10, 203) << endl;
  42.  
  43. 	cout << callcallA(call1, mul, 7, 111) << endl;
  44. 	cout << callcallA(call2, mul, 7, 111) << endl;
  45.  
  46. 	cout << callcallB(call1, mul, 7, 111) << endl;
  47. 	cout << callcallB(call2, mul, 7, 111) << endl;
  48.  
  49. 	return 0;
  50. }
  51.  
  52. int call1(int (*f)(int, int), int a, int b) { // 関数ポインタそのまま
  53. 	return (*f)(a, b);
  54. }
  55.  
  56. int call2(FUNC f, int a, int b) {             // typedefすると簡潔に書ける
  57. 	return (*f)(a, b);
  58. }
  59.  
  60. int callcallA(CALL c, FUNC f, int a, int b) {
  61. 	return (*c)(f, a, b);
  62. }
  63.  
  64. int callcallB(int (*c)(int (*)(int, int), int, int), int (*f)(int, int), int a, int b) {
  65. 	return (*c)(f, a, b);
  66. }
  67.  
  68.  
  69. int add(int a, int b) {
  70. 	return a + b;
  71. }
  72.  
  73. int mul(int a, int b) {
  74. 	return a * b;
  75. }
Success #stdin #stdout 0s 3340KB
comments (?)
stdin 
Standard input is empty
stdout 
120
120
213
2030
213
2030
777
777
777
777
https://ideone.com/JUqX0t
language:
C++ (gcc 8.3)
created:
10 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!