c - 如何编写一个程序，让用户输入尽可能多的字符串并统计出现次数？

Question

我需要编写一个程序，让用户输入一个字符串，然后程序询问用户是否继续输入更多字符串。之后，程序应该计算用户输入的所有字符串中单词的所有出现次数。这段代码只计算最后一个字符串的出现次数，我应该如何更改它？

#include <stdio.h>
#include <string.h>
#define MAXSTRLEN 100

int main(void)
{
    int count = 0, c = 0, i, j = 0, k, space = 0;
    char p[50][100], str1[20], ptr1[50][100];
    char* ptr;
    char str[MAXSTRLEN], Y_or_N;
    printf("Write a sentence.\n");
    while (1)
    {
        gets(str);
        printf("Continue or not? (y or n): ");
        scanf("%c", &Y_or_N);
        getchar();
        if (Y_or_N == 'n')
            break;
    }
    for (i = 0; str[i] != '\0'; i++)
    {
        if ('A' <= str[i] && str[i] <= 'Z')
            str[i] = str[i] + 32;
    }
    for (i = 0; i < strlen(str); i++)
    {
        if ((str[i] == ' ') || (str[i] == ',' && str[i + 1] == ' ') || (str[i] == '.'))
        {
            space++;
        }
    }
    for (i = 0, j = 0, k = 0; j < strlen(str); j++)
    {
        if ((str[j] == ' ') || (str[j] == 44) || (str[j] == 46))
        {
            p[i][k] = '\0';
            i++;
            k = 0;
        }
        else
            p[i][k++] = str[j];
    }
    k = 0;
    for (i = 0; i <= space; i++)
    {
        for (j = 0; j <= space; j++)
        {
            if (i == j)
            {
                strcpy(ptr1[k], p[i]);
                k++;
                count++;
                break;
            }
            else
            {
                if (strcmp(ptr1[j], p[i]) != 0)
                    continue;
                else
                    break;
            }
        }
    }
    for (i = 0; i < count; i++)
    {
        for (j = 0; j <= space; j++)
        {
            if (strcmp(ptr1[i], p[j]) == 0)
                c++;
        }
        printf("%s : %d times.\n", ptr1[i], c);
        c = 0;
    }
}

Answer 1

暴力方法。时间复杂度可能是 O(N^2)。大约分为四个步骤:
1.输入循环('\n'将完成一个字符串输入)
2. 将字符串行拆分为单词列表。
3. 计算列表中每个单词的时间。 (暴力破解)
4. 打印结果。

#include <stdio.h>

#include <string.h>
#include <stdlib.h>
#include <stdbool.h>

#define MAXSTRLEN 1024

char **splitToList(char *a, int *rowSize) {
    char **b=NULL;
    int start=0;
    int count=0;
    for (int i = 0; i < strlen(a); ++i) {
        if (' ' == a[start]) {
            start = i;
            continue;
        }

        if (' ' == a[i]) {
            ++count;
            if (NULL == b) {
                b = (char **)malloc(sizeof(char *));
                b[count-1] = (char *)malloc(sizeof(char)*(i-start+1));
                memcpy(b[count-1], &a[start], (i-start));
                b[count-1][i-start] = '\0';
                start = i;
            } else {
                b = (char **)realloc(b, sizeof(char *)*(count));
                b[count-1] = (char *)malloc(sizeof(char)*(i-start+1));
                memcpy(b[count-1], &a[start], (i-start));
                b[count-1][i-start] = '\0';
                start = i;
            }
            continue;
        }

    }

    if (start <= strlen(a) && a[strlen(a)-1] != ' ') {
        ++count;
        b = (char **)realloc(b, sizeof(char *)*(count));
        b[count-1] = (char *)malloc(sizeof(char)*(strlen(a)-start+1));
        memcpy(b[count-1], &a[start], (strlen(a)-start));
        b[count-1][strlen(a)-start] = '\0';
    }

    *rowSize = count;

    return b;
}

bool equalChars(char *a, char *b) {
    if (strlen(a) != strlen(b)) {
        return false;
    }

    int i=0;
    while (i<strlen(a) && a[i] == b[i]) {
        ++i;
    }

    if (i < strlen(a)) {
        return false;
    }

    return true;
}

void countWords(char *a) {
    int *rowSize = (int *)malloc(sizeof(int));

    // 1. split to word list
    char **b = splitToList(a, rowSize);

    // 2. count words times
    int count[*rowSize];
    for (int i = 0; i < *rowSize; ++i) {
        if (0 == i) {
            count[i] = 1;
            continue;
        }
        int dup = false;
        for (int j = 0; j <= i-1 ; ++j) {
            if (equalChars(b[i], b[j])) {
                count[j] = count[j] + 1;
                count[i] = 0;
                dup = true;
                break;
            }
        }

        if (!dup) {
            count[i] = 1;
        }
    }

    // 3. print words times
    for (int i = 0; i < *rowSize; ++i) {
        if (count[i] != 0) {
            printf("word: %s, times: %d\n", b[i], count[i]);
        }
    }
}

int main(void) {

    char *a = (char *)malloc(MAXSTRLEN);
    int curLen = -1;

    // input loop
    int c;
    for(;;) {
        c = fgetc(stdin);
        if(c == EOF) {
            break;
        }

        if (curLen > MAXSTRLEN - 1) {
            break;
        }

        if(c == '\n') {
            a[++curLen] = '\0';
            countWords(a);
            curLen=-1;
        } else {
            a[++curLen] = (char) c;
        }
    }

}