上机实验（02次）

代码

sorry,之前写的有bug。现在的已经完全没有bug了。

#include 
#include 

#define MIN 32767
#define MAX 500

typedef struct
{
    char data;
    double weight;
    int parent;
    int lchild;
    int rchild;
} HTNode;

typedef struct
{
    char cd[MAX];
    int start;
} HCode;

void Display0(int count[]);                                  //统计各个字符出现次数
void Display1(HTNode ht[], HCode hcd[], int n0, char str[]); //显示各个字符的哈夫曼编码并输出电文
void Display2(HTNode ht[], int n0, char str[]);              //输入电文解码输出字符串
void BuildHTArray(HTNode ht[], int count[]);                 //填充ht[]数组的前n0项的data域和weight域
void CreateHT(HTNode ht[], int n0);                          //构造哈夫曼树
void CreateHCode(HTNode ht[], HCode hcd[], int n0);          //求哈夫曼编码

void Display0(int count[])
{
    printf("Character\tfrequency\n");
    for (int i = 0; i < 127; i++)
    {
        if (count[i] != 0)
        {
            printf("%c:\t%d\n", i, count[i]);
        }
    }
}

void Display1(HTNode ht[], HCode hcd[], int n0, char str[])
{
    printf("character\tHuffmanCode\n");
    for (int i = 0; i < n0; i++)
    {
        printf("%c:\t", ht[i].data);
        for (int j = hcd[i].start; j <= n0; j++)
        {
            printf("%c", hcd[i].cd[j]);
        }
        printf("\n");
    }
    printf("\nThe HCode of this str is: ");
    while (*str != '\0')
    {
        for (int i = 0; i < n0; i++)
        {
            if (ht[i].data == *str)
            {
                for (int k = hcd[i].start; k <= n0; k++ )
                {
                    printf("%c", hcd[i].cd[k]);
                }
                break;
            }
        }
        str++;
    }
    printf("\n");
}

void Display2(HTNode ht[], int n0, char str[])
{
    int i = 0, j = 2 * n0 - 2, prej;
    printf("The str of this HCode is: ");
    while (str[i] != '\0')
    {
        while (j != -1)
        {
            prej = j;
            if (str[i] == '0')
            {
                j = ht[j].lchild;
            }
            else
            {
                j = ht[j].rchild;
            }
            i++;
        }
        printf("%c", ht[prej].data);
        i--;
        j = 2 * n0 - 2;
    }
    printf("\n");
}

void BuildHTArray(HTNode ht[], int count[])
{
    int j = 0;
    for (int i = 0; i < 127; i++)
    {
        if (count[i] != 0)
        {
            ht[j].data = i;
            ht[j].weight = count[i];
            j++;
        }
    }
}

void CreateHT(HTNode ht[], int n0)
{
    int i, k, lNode, rNode;
    double min1, min2;
    for (i = 0; i < 2 * n0 - 1; i++)
    {
        ht[i].lchild = ht[i].parent = ht[i].rchild = -1;
    }
    for (i = n0; i <= 2 * n0 - 2; i++)
    {
        min1 = min2 = MIN;
        lNode = rNode = -1;
        for (k = 0; k <= i - 1; k++)
        {
            if (ht[k].parent == -1)
            {
                if (ht[k].weight < min1)
                {
                    min2 = min1;
                    rNode = lNode;
                    min1 = ht[k].weight;
                    lNode = k;
                }
                else if (ht[k].weight < min2)
                {
                    min2 = ht[k].weight;
                    rNode = k;
                }
            }
        }
        ht[i].weight = ht[lNode].weight + ht[rNode].weight;
        ht[i].lchild = lNode;
        ht[i].rchild = rNode;
        ht[lNode].parent = i;
        ht[rNode].parent = i;
    }
}

void CreateHCode(HTNode ht[], HCode hcd[], int n0)
{
    int i, parent, child;
    HCode hc;
    for (i = 0; i < n0; i++)
    {
        hc.start = n0;
        parent = ht[i].parent;
        child = i;
        while (parent != -1)
        {
            if (ht[parent].lchild == child)
            {
                hc.cd[hc.start--] = '0';
            }
            else
            {
                hc.cd[hc.start--] = '1';
            }
            child = parent;
            parent = ht[child].parent;
        }
        hc.start++;
        hcd[i] = hc;
    }
}

int main(void)
{
    FILE *fp;
    char ch, str[MAX + 1];
    int count[127] = {0}, n0 = 0, i = 0;
    fp = fopen("text.txt", "r");
    if (fp)
    {
        while (fscanf(fp, "%c", &ch) != EOF)
        {

            if (count[ch] == 0)
            {
                n0++;
            }
            count[ch]++;
            str[i++] = ch;
        }
        str[i] = '\0';
    }
    fclose(fp);
    HTNode *pHT = (HTNode *)malloc((2 * n0 - 1) * sizeof(HTNode));
    HCode *pHCD = (HCode *)malloc((2 * n0 - 1) * sizeof(HCode));
    if(pHT==NULL||pHCD==NULL){
        return 1;
    }
    Display0(count);
    printf("\n\n");
    BuildHTArray(pHT, count);
    CreateHT(pHT, n0);
    CreateHCode(pHT, pHCD, n0);
    Display1(pHT, pHCD, n0, str);
    printf("\nPlease enter a string of Huffman code: ");
    gets(str);
    Display2(pHT, n0, str);
    getchar();
    getchar();
    return 0;
}

text.txt

renshengruozhiruchujian

运行结果

运行结果