Question

我尝试在C中实现动态数组，每次发现堆栈已满时大小加倍。当我尝试推送超过8个元素时，它会失败。它给出的输出是：

stack empty (since nothing is pushed on to it yet)
|1|
yes (indicates: double operation called)
|2|
yes
|3|
|4|
yes
|5|
|6|
|7|
|8|
yes

任何人都可以解释为什么它仅适用于最大为8的堆栈大小（n <= 8，在main中）感谢

代码：＃包括的#include

struct stkarr{              //structure for a node
     int top;
     int capacity;
     int *arr;
};

struct stkarr* buildstk(){ //build an object stack (s)
    struct stkarr *s = (struct stkarr*)malloc(sizeof(struct stkarr));
    // since it's a dynamic array we start with capacity = 1
    s->capacity=1;
    s->top=-1;
    s->arr = (int*)malloc(s->capacity*sizeof(int));
    return s;
};

int is_stk_full(struct stkarr* s){
    return(s->top==s->capacity-1); // 1->yes, 0->no
}

int is_stk_empty(struct stkarr* s){
    return(s->top==-1);
}

void dbl_stk(struct stkarr *s){//doubling the size of stack
    (s->capacity)*=2;
    s->arr = realloc(s->arr,s->capacity);
}

void psh(struct stkarr* s,int val){ //push
    if(is_stk_full(s)){
    printf("yes\n");
    dbl_stk(s);
    }
        s->arr[++s->top] = val;
}

int pop(struct stkarr* s){
    if(is_stk_empty(s)){
        printf("stack empty\n");
        return;
    }
    else{
        return s->arr[s->top--];
    }
}

int main(){
    struct stkarr* s;
    int i,n;
    n=10;
    s = buildstk();
    //checking empty stack exception
    pop(s);

    for(i=0;i<n;i++){
        //push operation
        psh(s,i+1);
        printf("|%d|\n",pop(s)); // just checking if i+1 is pushed or not
        psh(s,i+1); // since I popped i+1, pushing it again on to stack
    }

    //never reaches here for n>8
    for(i=0;i<n;i++){//popping elements and printing them
        //pop operation
        printf("|%d|\n",pop(s));
    }

    return 0;
}

Answer 1

你的缓冲区不够大。 realloc(s->arr,s->capacity);应为realloc(s->arr,s->capacity * sizeof(int));

任何人都可以解释C中动态堆栈的这种实现的输出

1 个答案: