栈的基本操作--插入，取栈顶元素，删除栈顶，清空栈
试了机组数据都对了。我忘了一部分c语言容错的语句了，没办法写得尽如人意。
#include<iostream>#include<stdlib.h>using namespace std;struct stack{int size;int *top,*base;};stack a;const int stacksize=10;int top(){int e;if(a.top==a.base)return -1;e=*(a.top-1);return e;}void insert(int e){if(a.top-a.base>=a.size){a.base=(int*)realloc(a.base,(a.size+stacksize)*sizeof(int));a.top=a.base+a.size;a.size=a.size+stacksize;}*a.top=e;a.top=a.top+1;}void pop(){if(a.top==a.base){cout<<"error"<<endl;return;}a.top-=1;}void clear(){while(a.top>a.base){pop();}}int main(){int n,i,traget,ko;a.size=stacksize;a.base=(int*)malloc(a.size*sizeof(int));a.top=a.base;cin>>n;for(i=1;i<=n;i++){if(a.top-a.base>=a.size){a.base=(int*)realloc(a.base,(a.size+stacksize)*sizeof(int));if(!a.base)exit(OVERFLOW);a.top=a.base+a.size; a.size=a.size+stacksize;}cin>>*a.top;a.top=a.top+1;}cout<<top()<<endl;cin>>ko;insert(ko);cout<<top()<<endl;pop();cout<<top()<<endl;system("pause");return 0;}