c中动态使用数组

#include <iostream>
#include <fstream>
#include<stdlib.h>
#define MAXNUM 200
int Isood(int n);

using namespace std;

int main(void)
{
    int n;
    cout<<"input n:";
    cin>>n;

    int *p;
    p=(int *)malloc(n*sizeof(int));
    for(int i=;i<n;i++)
    {
        p[i]=i;
    }
    for(int i=;i<n;i++)
    {
        cout<<p[i]<<" ";
    }

    free(p);
}

main(){
    struct stu{
        int num;
        char *name;
        char sex;
        float score;
    }  *ps;
    ps=(struct stu*)malloc(sizeof(struct stu));
    ps->num=102;
    ps->name="Zhang ping";
    ps->sex='M';
    ps->score=62.5;
    printf("Number=%d\nName=%s\n",ps->num,ps->name);
    printf("Sex=%c\nScore=%f\n",ps->sex,ps->score);
    free(ps);
}