C 函数指针 参数传递

代码

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#include<iostream>
using namespace std;

// 函数指针
void (*pfun)(int *);
// 重定义函数指针
typedef void (*pFun)(int &);

// 指针函数
int * sub(int *a, int *b)
{

    int * s;
    int c;
    c = (*a)+(*b);
    s = &c;
    return s;
}

void test(int a)
{
    a += 1;
}

void test_1(int * a)
{
    *a = *a+1;
}

void test_2(int &a)
{
    a = a+1;
}

void test_3(pFun pfun, int &a)
{
    pfun(a);
}

int main(void)
{
    int *p;
    int a = 3, b = 4;
    p = sub(&a, &b);
    cout<<"a+b="<<*p<<endl;
    test(a);
    cout<<"a = "<<a<<endl;
    test_1(&a);
    cout<<"a = "<<a<<endl;
    test_2(a);
    cout<<"a = "<<a<<endl;
    test_3(test_2, a);
    cout<<"a = "<<a<<endl;
    pfun = test_1;
    (*pfun)(&a);
    cout<<"a = "<<a;
    return 0;
}

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运行结果

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a+b=7
a = 3
a = 4
a = 5
a = 6
a = 7