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#include "stdio.h"
#include "malloc.h"
#define MAX 100
typedef struct SeqStack
{
    int s[MAX];
    int t;
}*PSeqStack;
PSeqStack createEmptyStack_seq()
{
    PSeqStack pastack;
    pastack=(SeqStack*)malloc(sizeof(SeqStack));
    if(pastack==NULL)
        printf("Out of space!\n");
    else
        pastack->t=-1;
    return pastack;
}
int isEmptyStack_seq(PSeqStack pastack)
{
    return (pastack->t==-1);
}
void push_seq(PSeqStack pastack,int x)
{
    if(pastack->t>=MAX-1)
        printf("Overflow!\n");
    else
    {
        pastack->t=pastack->t+1;
        pastack->s[pastack->t]=x;
    }
}
void pop_seq(PSeqStack pastack)
{
    if(pastack->t==-1)
        printf("Underflow!\n");
    else
        pastack->t=pastack->t-1;
}
int top_seq(PSeqStack pastack)
{
    return(pastack->s[pastack->t]);
}
int main()
{
    PSeqStack pastack;
    int N;
    printf("Please input number to N!\n");
    scanf("%d",&N);
    pastack=createEmptyStack_seq();
    for(int i=0;i<N;i++)
    {
        int x;
        printf("Please input number to stack!\n");
        scanf("%d",&x);
        push_seq(pastack,x);
    }
    printf("The top number is %d",top_seq(pastack));
}