c - 在句子中颠倒单词

Question

我目前正在通过 K.N. King 的 C 编程:一种现代方法。我已经完成了第 8 章(数组)的课文，我迫不及待地想继续学习第 9 章，但我还没有解决每章末尾所谓的“编程项目”。不幸的是，第 14 号......让我烦恼。

Write a program that reverses the words in a sentence.

Enter a sentence: you can cage a swallow can't you?
Reversal of sentence: you can't swallow a cage can you?

Hint: Use a loop to read the characters one by one and store them in a one-dimensional char array. Have the loop stop at a period, question mark, or exclamation point (the "terminating character "), which is saved in a separate char variable. Then use a second loop to search backward through the array for the beginning of the last word. Print the last word, then search backward for the next-to-last word. Repeat until the beginning of the array is reached. Finally, print the terminating character.

我一直在考虑将单词定义为空格之间的一系列字符。因此，当到达一个空格时，向后打印每个字符，直到找到另一个空格。我的程序的第一个 版本只打印了第一个词。它的当前 版本只打印其他单词。我已经坚持了两天，所以非常感谢任何帮助。这是我的代码，以及一个输出示例。希望我已经正确记录了我的代码。提前致谢!

代码

/* Include the standard I/O library */
#include<stdio.h>

/* Define main */
int main(void) {

    /**
     * Declare an array of characters storing the sentence, as well as
     * a character representing the current character under cursor and
     * the terminating character
     */
    char sentence[100] = { ' ' }, c, tc;

    /**
     * Declare a loop counter already initialized at 0, an incremental
     * variable, as well as the size of the read sentence
     */
    int i = 0, j = 1, size = 0;

    /* Get the sentence */
    printf("Enter a sentence: \n");
    for(c = getchar(); (c != '.') && (c != '!') && 
        (c != '?') && (c != '\n'); c = getchar(), i++) {

        sentence[i] = c; /* Store the current character in the array */
        size++; /* Increase the sentence's size */
    }

    tc = c; /* Get the terminating character */

    /**
     * Go backward through the array, printing each sequence of characters
     * between spaces
     */
    for(i = 99; i >= 0; i--) {

        if(sentence[i] == ' ') {

            while(sentence[i + j] != ' ') {

                printf("%c", sentence[i + j]);
                j++;
            }

            j = 1; /* Reset the incremental variable */
            printf(" "); /* Print a tailing space */
        }
    }

    /**
     * Delete the tailing blank space and print the terminating character,
     * as well as a new line 
     */
    printf("\b%c\n", tc);

    return 0; /* Return 0 upon successful program execution */
}

输出:

http://drp.ly/1nYt5J

Answer 1

将每个单词压入堆栈并从索引 0 到 N-1 读取堆栈