嵌入式软件工程师C语言经典笔试2

1. 使用宏定义swap函数，不使用中间变量

#define swap(x,y) {(x) = (x) + (y);(y) = (x) - (y);(x) = (x) - (y)}

2. 实现字符串的反转

#define swap(x,y) {(x) = (x) + (y);(y) = (x) - (y);(x) = (x) - (y);}

void reverse(char *string)

{

    int len = strlen(string);

    char *begin = string;

    char *end = string + len - ;

    while (begin < end)

    {

            swap(*begin,*end);

        begin++;

        end--;

    }

}

3. 实现单链表的反转

　　3.1 方式一列表头不反转

void reverse_node(struct node *pHeader)

{

    struct node *p = pHeader->pNext;

    struct node *pbackup = NULL;

    if(NULL == pHeader || NULL == p)

    {

        printf("node should more one\n");

        return;

    }

    while(NULL != p)

    {

        pbackup = p->pNext;

        if(pHeader->pNext == p)

        {

            p->pNext = NULL;

        }

        else

        {

            p->pNext = pHeader->pNext;

            pHeader->pNext = p;

        }

        p = pbackup;

    }

}

　　3.2 方式二列表头也反转

struct node * reverse(struct node *pHeader)

{

    if (pHeader== NULL || pHeader-> Next == NULL)

    {

        return pHeader;

    }

    struct node *p = pHeader-> Next;

    struct node *pNewHeader =  reverse(p);

    p -> Next = pHeader;

    pHeader->Next = NULL;

    return pNewHeader;

}

4. 计算二叉树的高度

typedef struct BinTreeNode

{

    int data;

    struct BinTreeNode *lchild;

    struct BinTreeNode *rchild;

}*BSTree

int depth(BSTree T)

{

    if(!T)

    {

        return ;

    }

    int d1=depth(T->lchild);

    int d2=depth(T->rchild);

    return (d1>d2?d1:d2)+;

}

5. 判断一个数是否是2的次幂

inline int Is2exp(int i)

{

    return (i&（i-))?:);

}

巴特西

嵌入式软件工程师C语言经典笔试2

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