【问题标题】:Bubble sort dynamically created struct array in c冒泡排序在c中动态创建的结构数组
【发布时间】:2014-07-04 06:28:49
【问题描述】:

这里真的很新,很抱歉有任何进一步的错误.. 我有一些新的学校项目(学习 C),我必须连接到服务器 使用套接字而不是从服务器下载所有代码行。 之后,我需要对这些行进行排序,以便它们按顺序排列,我得到的位置在排序中。我已经下载了将它们保存在结构数组中的代码行,但现在我的冒泡排序向我显示了一些错误,我没有知道是什么问题..谢谢任何帮助。

typedef struct DATA{

    char* buf;
}DATA;
//  this fucntion creates a socket.
void sort_array(DATA *to_sort, int len){

    int i, j;
    char tmp[1024] = "";

    for (i = 0; i < len - 1; i++){
        for (j = 0; j < len - i - 1; j++){
            if (strcmp(to_sort[j].buf, to_sort[j + 1].buf) < 0){
                strcpy(tmp, to_sort[j + 1].buf);
                strcpy(to_sort[j + 1].buf, to_sort[j].buf);
                strcpy(to_sort[j].buf, tmp);
            }
        }
    }
}
int main(){

    WSADATA info;
    int error, s,j;
    int sendError, recvError;
    char buffer[1024] = "100",readbuf[1024] = "";
    char recvbuf[1024] = "";
    int numberLines, i, temp, convert;
    char converted_num[1024] = "";
    char *sub;
    struct sockaddr_in ClientService;
    FILE *fp = fopen("stored_data.txt", "w");
    FILE *ofp = fopen("final_result.txt", "w");
    DATA *to_sort = NULL;

    error = WSAStartup(MAKEWORD(2, 0), &info);
    //check if error occurred while configuring.
    if (error != 0){
        printf("WSAstartup failed with error: %d\n", error);
        exit(1);
    }
    s = socket_creation(fp);

    // configuration of the socket.
    ClientService.sin_family = AF_INET;
    ClientService.sin_addr.s_addr = inet_addr("54.209.143.42");
    ClientService.sin_port = htons(6714);
    connection(s, ClientService, fp); // function connecting to the server.

    error = WSAStartup(MAKEWORD(2, 0), &info);

    // send '100' login command to server.
    strcpy(buffer, "100");
    sendError = send_to_serv(buffer, s);

    // receiving respond  from the server.
    recvError = recv_from_serv(s, &numberLines, fp,buffer);

    // send '400' get number lines command to server.
    strcpy(buffer, "400");
    sendError = send_to_serv(buffer, s);

    // receiving respond from the server.
    recvError = recv_from_serv(s, &numberLines, fp,buffer);

    printf("\nNumber of Lines are: %d\n", numberLines);
    temp = numberLines; // number of all lines received.

    /* allocate mmoery for struct array to store the data from server */
    to_sort = (DATA*)malloc(sizeof(DATA)* temp);

    // getting the lines from the server.
    for (i = 0; i < temp; i++){
        j = 0;
        convert = 5000001 + i; // creating number of line wanted.
        _itoa(convert, converted_num, 10); // converting the int to a string (wanted line).
        sendError = send_to_serv(converted_num, s); // sending the server request of line wanted.
        recv_from_serv(s, &numberLines, fp, buffer); // receive the line wanted.
        sub = substring(buffer, 0, 3);

        // checks if the server returned '502 OK' or '501 REJECT'
        if (strcmp(sub, "502") != 0){
            to_sort[j].buf = buffer;
            j++;
        }
    }
    sort_array(to_sort, temp); // sorting the struct array.

    // printing the final result.

    // clean memoery.
    free(to_sort);
    fclose(fp);
    system("PAUSE>nul");
    return 0;
}

【问题讨论】:

  • 您应该删除所有不相关的(套接字和加载)代码,并制作一个包含您遇到问题的代码的程序,即排序。另外,为什么不使用qsort()
  • 哦,首先我很抱歉。不知道..第二个我不太好,我的老师让我不要用 qsort() 这样做
  • 你应该告诉我们你遇到了什么错误,并切断所有不相关的代码。
  • 好吧,我想我现在切断了所有不相关的代码,我得到的错误来自 sort_array 函数。它是Unhandled exception at 0x5EEB4282 (msvcr120d.dll) in C Project.exe: 0xC0000005: Access violation reading location 0xCDCDCDCD.@Theolodis @unwind
  • to_sort[j].buf = 缓冲区;指向所有指针的相同缓冲区的指针?恕我直言,需要初始化和复制。 2) j++ 仅在条件下。如果 502 则不要停止循环。 3) char 数组的 free(to_sort) 数组。然后释放所有数组,然后释放 to_sort 本身。

标签: c sockets client


【解决方案1】:
void bsort(char **data, size_t size) {
    size_t i, j;
    char *tmp = NULL;

    for (i = 1; i < size; i++) {
        for (j = 1; j < size; j++) {
            if (strcmp(data[j-1], data[j]) > 0) {
                tmp = data[j-1];
                data[j-1] = data[j];
                data[j] = tmp;
            }
        }
    }
}

此代码进行排序。我检查了)))需要更多时间。意思是试试这段代码,如果不行,再进一步检查错误。

to_sort[j] = (char*) malloc(1024);
memcpy(to_sort[j].buf, buffer, 1024);
j++;

我读取数据直到我得到完整的缓冲区。不要在每次数据到来时都尝试检查 502。只有一次,收到回复后。之后,您将响应流式传输直到结束。

#define REPLY 1024
do {
    bytes_read = recv(sock, server_reply, REPLY, 0);
    if (bytes_read == SOCKET_ERROR) {
        perror("error recieving data");
        exit(1);
    }
    if (bytes_read > 0) {
        to_sort[j] = (char*) malloc(1024);
        memcpy(to_sort[j].buf, server_reply, 1024);
        j++;
    }
} while (bytes_read == REPLY);

更新

void bsort(DATA *data, size_t size) {
    size_t i, j;
    DATA tmp;

    for (i = 1; i < size; i++) {
        for (j = 1; j < size; j++) {
            if (strcmp(data[j-1].buf, data[j].buf) > 0) {
                tmp = data[j-1];
                data[j-1] = data[j];
                data[j] = tmp;
            }
        }
    }
}

UPD2

//1) Simpliest way
//pointer to array
DATA *s = NULL;
//size of array
size_t array_size = 50;

//create array of DATA elements
s = (DATA *) malloc(sizeof(DATA) * array_size);
//now you have array of DATA. But each element contains uninitialized pointer
//of type char

//set each pointer to proper address on heap
//each element now can handle string length 1023
//note here all strings have same size
for (size_t i = 0; i < array_size; i++) {
    s[i].buf = (char*) malloc(1024);
}

免费

for (size_t i = 0; i < array_size; i++) {
    free(s[i].buf);
}
free(s);

排序

DATA *s = NULL;
size_t array_size = 5;
size_t i;

s = (DATA *) malloc(sizeof(DATA) * array_size);

for (i = 0; i < array_size; i++) {
    s[i].buf = (char*) malloc(1024);
}

strcpy(s[0].buf, "AAAAA");
strcpy(s[1].buf, "CCCCC");
strcpy(s[2].buf, "XXXXX");
strcpy(s[3].buf, "AAAAA");
strcpy(s[4].buf, "BBBBB");

bsort(s, 5);

for (i = 0; i < array_size; i++) {
    printf("%s\n", s[i]);
}

for (i = 0; i < array_size; i++) {
    free(s[i].buf);
}
free(s);

UPD3 更复杂的内存分配方式,但速度更快

DATA *s = NULL;
size_t array_size = 5;
size_t item_size = 1024;
size_t i;

s = (DATA *) malloc(sizeof(DATA) * array_size + array_size * item_size);
s[0].buf = (char*) (s + array_size);
for (size_t i = 0; i < array_size; i++) {
    s[i].buf = s[0].buf + i * item_size;
}

strcpy(s[0].buf, "AAAAA");
strcpy(s[1].buf, "CCCCC");
strcpy(s[2].buf, "XXXXX");
strcpy(s[3].buf, "AAAAA");
strcpy(s[4].buf, "BBBBB");

bsort(s, 5);

for (i = 0; i < array_size; i++) {
    printf("%s\n", s[i]);
}

free(s);

【讨论】:

  • 看,我不是在尝试对字符串数组进行冒泡排序,而是在尝试对字符串数组进行冒泡排序和struct 所以.. :S 谢谢你 :)
  • 您的结构仅包含一个字段,因此在 c 中它是相同的指针。您只需为其添加别名。
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