【DS】About Stack

#include<stdio.h>
#include<stdlib.h>

typedef struct Stack
{
    /*Stack has three properties.*/
    int capacity;    //the maximum number of elements stack can hold
    int size;    //current size of stack     
    int *elements;    //array of elements
}Stack;



Stack *createStack(int maxElements) 
{
    /*Create a Stack.*/
    Stack *S;
    S=(Stack*)malloc(sizeof(Stack));
    /*Initialize its properties*/
    S->elements=(int*)malloc(sizeof(int)*maxElements);
    S->size=0;
    S->capacity=maxElements;
    /*Return the pointer*/
    return S;
}


void pop(Stack *S)
{
    /*We cannot pop if its size is zero(as it‘s empty)*/
    if(S->size==0)
    {
        printf("Stack is Empty\n");
        return;
    }    
    /*Removing an element is equivalent to reducing its size by one!!!*/
    else
    {
        S->size--;
    }
    return;
} 


int top(Stack *S)
{
    if(S->size==0)
    {
        printf("Stack is Empty\n");
        exit(0);
    }
    /*Return the topmost element*/
    return S->elements[S->size-1];
}

void push(Stack *S,int element)
{
    int *newbase; 
    /*If the Stack is full,extend it*/
    if(S->size>=S->capacity)
    {
        printf("Stack is Full\n");
        newbase=(int*)realloc(S->elements,(S->size+1)*sizeof(int));
        S->elements=newbase;    
        S->capacity++;    
    }
    else
    {
        /*Push the new element on the top of the Stack and increase its size*/
        S->elements[S->size++]=element;
    }
    return;
}


int main()
{
    int i;
    int e;
    int n=random()%50; //set n as the capacity
    printf("next!\n");
    Stack *S=createStack(n);    
    for(i=0;i<n;i++)
    {    
        e=random()%100;
        push(S,e);
        printf("%d ",e);
    }
    printf("\nTop element is %d\n",top(S));
    pop(S);
    printf("After the first pop,top element is:%d\n",top(S));
    pop(S);
    printf("After the second pop,top element is:%d\n",top(S));
    pop(S);
    printf("After the third pop,top element is:%d\n",top(S));
}

//将上面的测试主函数替换为下面一个主函数加一个转换函数

void convert(int n)
{
    Stack *S=createStack(10);
    int e;
    while(n!=0)
    {
        push(S,n%8);
        n/=8;
    }
    while(S->size!=0)
    {
        pop(S);
        printf("%d",S->elements[S->size]);
    }
} 

int main()
{
    convert(1348);
}