指针与内存

# include "stdio.h"# include "iostream.h"# include "malloc.h"# include "string.h"//关于函数赋值void fun1(int num1,int num2){    cout<<"fun1():"<<endl<<"num1="<<num1<<"  "<<"num2="<<num2<<endl;    int temp=num1;    num1=num2;    num2=temp;    cout<<"num1="<<num1<<"  "<<"num2="<<num2<<endl;}void fun2(int *p1,int *p2){    cout<<"fun2():"<<endl<<"*p1="<<*p1<<"  "<<"*p2="<<*p2<<endl;    int * pt=p1;    p1=p2;    p2=pt;    cout<<"*p1="<<*p1<<"  "<<"*p2="<<*p2<<endl;}void fun3(int *p1,int *p2){    cout<<"fun2():"<<endl<<"*p1="<<*p1<<"  "<<"*p2="<<*p2<<endl;    int temp=*p1;    *p1=*p2;    *p2=temp;    cout<<"*p1="<<*p1<<"  "<<"*p2="<<*p2<<endl;}//关于内存/*编译成功但是程序存在问题，p指针指向的内存空间没有被释放（因为在堆空间中）要释放free(p)。*/void mem1(){    char * p=(char *)malloc(20);    strcpy(p,"hello");    printf("*p=%s\n",p);    //cout<<*p;只输出h    free(p);}void main(){    int a=10,b=20;//  fun1(a,b);//  cout<<"执行fun1()"<<"a="<<a<<"  "<<"b="<<b<<endl;//  fun2(&a,&b);//  cout<<"执行fun2()"<<"a="<<a<<"  "<<"b="<<b<<endl;//  fun3(&a,&b);//  cout<<"执行fun3()"<<"a="<<a<<"  "<<"b="<<b<<endl;    mem1();}