c - 纯C字符串替换整个单词

我很难在一个句子中替换整个单词。

例如:

更换:

the到a

hello到hi

house到tree

输入:



输出:



是否可以仅使用<string.h>库而不使用Regex等来实现？

最佳答案

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

typedef struct pair {
    char *key;
    char *value;
} Pair;

int cmp(const void *a, const void *b){
    return strcmp(((const Pair*)a)->key, ((const Pair*)b)->key);
}

char *dictionary(const char *word){
    static const Pair table[] =
        {{"hello", "hi"}, {"house", "tree"},{"the", "a"}};
    char *p, *wk = strdup(word);
    Pair key, *pair;

    for(p=wk;*p;++p)
        *p = tolower(*p);
    key.key = wk;
    pair=bsearch(&key, table, sizeof(table)/sizeof(Pair), sizeof(Pair), cmp);
    free(wk);
    if(pair){
        wk=strdup(pair->value);
        if(isupper(*word))
            *wk = toupper(*wk);//capitalize
        return wk;
    }

    return NULL;
}

typedef char Type;

typedef struct vector {
    size_t size;
    size_t capacity;
    Type *array;
} Vector;

Vector *vec_make(){
    Vector *v;
    v = (Vector*)malloc(sizeof(Vector));
    if(v){
        v->size = 0;
        v->capacity=16;
        v->array=(Type*)realloc(NULL, sizeof(Type)*(v->capacity += 16));
    }
    return v;
}

void vec_add(Vector *v, Type value){
    v->array[v->size] = value;
    if(++v->size == v->capacity){
        v->array=(Type*)realloc(v->array, sizeof(Type)*(v->capacity += 16));
        if(!v->array){
            perror("memory not enough");
            exit(-1);
        }
    }
}
void vec_adds(Vector *v, Type *values, size_t size){
    while(size--)
        vec_add(v, *values++);
}

char *convert(const char *str){
    static const char *delimiters = " \t\n,.!?";
    char *in = strdup(str);
    char *out;
    char *inp = in;
    Vector *v = vec_make();

    while(*inp){
        size_t size;
        if(size = strcspn(inp, delimiters)){
            char *word, *cnv_word;
            word = malloc(size+1);
            memcpy(word, inp, size);
            word[size]='\0';
            if(NULL==(cnv_word = dictionary(word)))
                vec_adds(v, word, size);
            else
                for(out = cnv_word; *out; ++out)
                    vec_add(v, *out);
            free(word);
            free(cnv_word);
            inp += size;
        }
        if(size = strspn(inp, delimiters)){
            vec_adds(v, inp, size);
            inp += size;
        }
    }
    vec_add(v, '\0');
    out = v->array;
    free(v);
    free(in);

    return out;
}

int main(void){
    char input[] = "Hello there, this is the house.";
    char *output = convert(input);

    puts(input);
    puts(output);
    free(output);

    return 0;
}
/* result
Hello there, this is the house.
Hi there, this is a tree.
*/