بخش ۱۶ - اشاره‌گر به تابع

#include <iostream>
using namespace std;

void print(int x) {
    cout << x << endl;
}

void print_twice(int x) {
    cout << x << ' ' << x << endl;
}

int main() {
    void (*func_ptr)(int);

    func_ptr = print;
    func_ptr(10);

    func_ptr = print_twice;
    func_ptr(20);
}
					

#include <iostream>
using namespace std;

typedef void (*func_ptr_type)(int);

void print(int x) {
    cout << x << endl;
}

void print_twice(int x) {
    cout << x << ' ' << x << endl;
}

int main() {
    func_ptr_type fp;

    fp = print;
    fp(10);
}
					

#include <iostream>
using namespace std;

typedef int (*binop)(int, int);

int f(binop op, int x, int y, int z) {
    return op(op(x, y), z);
}

int add(int a, int b) { return a + b; }
int sub(int a, int b) { return a - b; }

int main() {
    cout << f(add, 1, 3, 5) << endl;
    cout << f(sub, 1, 3, 5) << endl;
}
					

#include <iostream>
#include <string>
#include <map>
using namespace std;

typedef int (*operation)(int, int);

int add(int a, int b) { return a + b; }
int mult(int a, int b) { return a * b; }
int sub(int a, int b) { return a - b; }
int divide(int a, int b) { return a / b; }

int main() {
    string s;
    cin >> s;

    map<char, operation> ops;
    ops['+'] = add;
    ops['-'] = sub;
    ops['*'] = mult;
    ops['/'] = divide;

    int result = s[0] - '0';
    for (int i = 1; i < s.length(); i += 2)
        result = ops[s[i]](result, s[i+1]-'0');

    cout << result << endl;
}