Question

我尝试构建可以反转字符串单词的代码：

input: Hello World!
output:olleH !dlroW

我不能使用任何指针我构建的代码是，有一个函数可以得到句子列表地址（最多20行的矩阵） - 表格，表格中的句子数量和我想要改变的句子数量。

int changeCharOrder(char table[][MAX_SENTENCE_LENGTH], int numOfSentences, int sentenceToChange) {
    int slen, slen2, slenrev, lastwordlen=0, c=0, i, q, f, start=0;
    char reversed[MAX_SENTENCE_LENGTH]; // the reversed sentence will be here
    char oneword[MAX_SENTENCE_LENGTH];  // i tried to split the sentence to words and then reverse them
    reversed[0] = '\0';
    slen = strlen(table[sentenceToChange]);
    for (i = 0; i < slen; i++) { //for loop to looking for space or EOS
        while((table[sentenceToChange][i] != ' ') && (table[sentenceToChange][i] != '\0')) {
            oneword[c] = table[sentenceToChange][i]; // copy the word and save in oneword
            i++;
            c++;
        }

        oneword[i+1] = '\0';
        slen2 = strlen(oneword);
        slenrev = strlen(reversed);
        for(q = i+slen2-1; q > i; q--){ // here is the reversing code. it's not working well 
            reversed[q-1] = table[sentenceToChange][start];
            start++;
        }
        start++;
        lastwordlen = strlen(oneword);
        reversed[slen] = '\0';
        c = 0;
    }
    reversed[slen] = '\0';
    printf("%s",reversed);  
}

它没有按预期工作。我只能反转第一个单词。有什么建议？感谢

Answer 1

#include <stdio.h>

int main( void ){
    char sentence[] = "Hello World!";
    int i, word_top, word_end;
    for(i=0; sentence[i]; ++i){
        if(sentence[i] == ' ')
            continue;
        word_end = word_top = i;
        while(sentence[word_end] && sentence[word_end] != ' ')
            ++word_end;
        i = --word_end;//move back one
        while(word_end > word_top){
            //swap top and end
            char temp = sentence[word_top];
            sentence[word_top++] = sentence[word_end];
            sentence[word_end--] = temp;
        }
    }
    puts(sentence);
    return 0;
}

Answer 2

试试这个

for (i=0; i<slen; i++) { //for loop to looking for space or EOS
    while((table[sentenceToChange][i]!=' ')&&(table[sentenceToChange][i]!='\0')) {
        oneword[c] = table[sentenceToChange][i]; // copy the word and save in oneword
        i++;
        c++;
    }

    oneword[i]='\0';
    c--;
    slen2=strlen(oneword);
    slenrev=strlen(reversed);
    for(q=c;c>=0;c--){  //you can remove `q=c` also 'for(;c>=0;c--)' will also work
        reversed[start]=oneword[c]; 
        start++;
    }
    reversed[start++]=' ';
    reversed[start]='\0';
    c=0;
}
printf("\n%s",reversed);

Answer 3

这是另一个类似的情况

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

#define MAX_SENTENCE_LENGTH 30

int changeCharOrder(char table[][MAX_SENTENCE_LENGTH], int sentenceToChange) {
    int i=0, j, k;
    char *sptr = table[sentenceToChange];     // make code more readable
    char reversed[MAX_SENTENCE_LENGTH];       // reversed words will be here
    strcpy (reversed, sptr);                  // copy source spaces and terminator
    while (sptr[i]) {                         // until end of string
        while (sptr[i] > 0 && sptr[i] <= ' ') // find first char
            i++;
        j = i;
        while (sptr[j] > ' ')                 // find end of word
            j++;
        k = j;                                // where word ended
        while (i < j)                         // reverse the word
            reversed[i++] = sptr [--k];
    }
    printf("%s\n%s\n\n", sptr, reversed);  
}

int main(void)
{
    char sents [3][MAX_SENTENCE_LENGTH] = 
            {"Hello World!", "Second sentence", " Three   words here   ."};
    changeCharOrder (sents, 0);
    changeCharOrder (sents, 1);
    changeCharOrder (sents, 2);
    return 0;
}

节目输出：

Hello World!
olleH !dlroW

Second sentence
dnoceS ecnetnes

 Three   words here   .
 eerhT   sdrow ereh   .

在C中反转字符串

3 个答案: