如何从字符串中取出单词并将它们放入字符串数组中？在C中 [英] How to get words out of a string and put them in an string array ? In C
问题描述
我基本上是在一个字符串中包含一个句子，并希望将其分解为每个单词。每个单词都应放入字符串数组中。我不允许使用 strtok 。我有此代码，但无法正常工作。有人可以帮忙吗？
I basically have a sentence in a string and want to break it down word per word. Every word should go into an array of strings. I am not allowed to use strtok. I have this code but it doesn't work. Can someone help?
肯定可以在互联网上找到类似的东西，但我找不到任何东西...
There is for sure something similar in the internet but I couldn't find anything...
int main(){
char s[10000]; // sentence
char array[100][100]; // array where I put every word
printf("Insert sentence: "); // receive the sentence
gets(s);
int i = 0;
int j = 0;
for(j = 0; s[j] != '\0'; j++){ // loop until I reach the end
for(i = 0; s[i] != ' '; i++){ // loop until the word is over
array[j][i] = s[i]; // put every char in the array
}
}
return 0;
}
推荐答案
每个单词都应放入字符串数组中。我不允许使用
strtok。
有趣的问题可以用紧凑的算法解决。
它处理 check（char c）中指定的多个空格和标点符号。
Interesting problem which could be resolved in a compact algorithm.
It handles multiple spaces and punctuation marks specified in check(char c).
最困难的问题的一部分是正确处理极端情况。当单词的长度超过 WORD_LEN 的长度，或者单词的数量超过 array 的容量时，我们可能会遇到这种情况。
The most difficult part of the problem is to properly handle corner cases. We may have situation when words are longer more than WORD_LEN length or the number of words exceeds the capacity of the array.
这两种情况都得到了妥善处理。该算法会截断多余的单词，仅解析为数组的容量。
Both cases are properly handled. The algorithm truncates the excessive words and parses only to the capacity of the array.
（顺便说一句。请勿使用 gets ：为什么gets函数如此危险，以至不应该使用它？）
(BTW. Do not use gets: Why is the gets function so dangerous that it should not be used?)
编辑：已提供经过充分测试的 find_tokens 函数。
The fully tested find_tokens function has been presented.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define WORD_LEN 3 // 100 // MAX WORD LEN
#define NR_OF_WORDS 3 // 100 // MAX NUMBER OF WORDS
#define INPUT_SIZE 10000
int is_delimiter(const char * delimiters, char c) // check for a delimiter
{
char *p = strchr (delimiters, c); // if not NULL c is separator
if (p) return 1; // delimeter
else return 0; // not a delimeter
}
int skip(int *i, char *str, int skip_delimiters, const char *delimiters)
{
while(1){
if(skip_delimiters) {
if( (str[(*i)+1] =='\0') || (!is_delimiter(delimiters, str[(*i)+1])) )
break; // break on nondelimeter or '\0'
else (*i)++; // advance to next character
}
else{ // skip excess characters in the token
if( is_delimiter(delimiters, str[(*i)]) )
{
if( (str[(*i)+1] =='\0') || !is_delimiter(delimiters, str[(*i)+1]) )
break; // break on non delimiter or '\0'
else (*i)++; // skip delimiters
}
else (*i)++; // skip non delimiters
}
}
if ( str[(*i)+1] =='\0') return 0;
else return 1;
}
int find_tokens(int max_tokens, int token_len, char *str, char array[][token_len+1], const char *delimiters, int *nr_of_tokens)
{
int i = 0;
int j = 0;
int l = 0;
*nr_of_tokens = 0;
int status = 0; // all OK!
int skip_leading_delimiters = 1;
int token = 0;
int more;
for(i = 0; str[i] != '\0'; i++){ // loop until I reach the end
// skip leading delimiters
if( skip_leading_delimiters )
{
if( is_delimiter( delimiters, str[i]) ) continue;
skip_leading_delimiters = 0;
}
if( !is_delimiter(delimiters,str[i]) && (j < token_len) )
{
array[l][j] = str[i]; // put char in the array
//printf("%c!\n", array[l][j] );
j++;
array[l][j] = 0;
token = 1;
}
else
{
//printf("%c?\n", str[i] );
array[l][j] = '\0'; // token terminations
if (j < token_len) {
more = skip(&i, str, 1, delimiters); // skip delimiters
}
else{
more = skip(&i, str, 0, delimiters); // skip excess of the characters in token
status = status | 0x01; // token has been truncated
}
j = 0;
//printf("more %d\n",more);
if(token){
if (more) l++;
}
if(l >= max_tokens){
status = status | 0x02; // more tokens than expected
break;
}
}
}
if(l>=max_tokens)
*nr_of_tokens = max_tokens;
else{
if(l<=0 && token)
*nr_of_tokens = 1;
else
{
if(token)
*nr_of_tokens = l+1;
else
*nr_of_tokens = l;
}
}
return status;
}
int main(void){
char input[INPUT_SIZE+1]; // sentence
char array[NR_OF_WORDS][WORD_LEN+1]; // array where I put every word, remeber to include null terminator!!!
int number_of_words;
const char * delimiters = " .,;:\t"; // word delimiters
char *p;
printf("Insert sentence: "); // receive the sentence
fgets(input, INPUT_SIZE, stdin);
if ( (p = strchr(input, '\n')) != NULL) *p = '\0'; // remove '\n'
int ret = find_tokens(NR_OF_WORDS, WORD_LEN, input, array, delimiters, &number_of_words);
printf("tokens= %d ret= %d\n", number_of_words, ret);
for (int i=0; i < number_of_words; i++)
printf("%d: %s\n", i, array[i]);
printf("End\n");
return 0;
}
测试：
Insert sentence: ..........1234567,,,,,,abcdefgh....123::::::::::::
tokens= 3 ret= 1
0: 123
1: abc
2: 123
End
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