Question

我试图通过创建一个水平方向的直方图来解决K＆amp; R C练习1-13，该直方图测量用户输入中不同长度的单词的频率。这是我的代码：

#include <stdio.h>

main(){

int a, b, c, d;                                 //array_position, word_length, getchar(), word_count
int y[10];                                      //array representing word lengths from 1-10 letters

b =  0;                                         //word_length initializes with a zero value
a = 1;                                          //array_position initializes with a value of one (no words contain zero characters)


for(y[a] = 0; (c = getchar()) != EOF;){         //current array position initializes with a zero value, and c initializes as the current input character
    if(c != ' ' && c != '\n' && c != '\t')      //if c is anything other than a blank, newline or tab
        ++b;                                     //increment the word_length by one
    else                                        //otherwise
        ++a;                                    //increment the array_position by one
        b = 0;                                  //and reset the word_length to zero
}

a = 1;                                          //reset the array_position to one

do{
    if(y[a] > 0){                               //if current array_position holds a value greater than 0
        printf("%i",a);                         //print the name of the array_position (1,2,3...)
        for(d = 0; d < y[a]; ++d){              //reset the word_length--if the word_length is less than the value contained in the current array position, increment the word length by one
            putchar('-');                       //print a dash and re-evaluate the condition
        }
        if(d == y[a]){                          //when the word_length is equal to the value contained in the current array position
            putchar('-');                       //print a final dash
            putchar('\n');                      //and a newline
        }
    }
    ++a;                                        //increment the array position by one
}while(a > 11);                                 //repeat until the current array position is 11
}

该代码旨在生成一个非常简单的图表，看起来像这样，排序长度为1-10个字符的单词：

1---
2----------
3-----
4--

等等。它还将省略任何未被输入中的一个或多个单词表示的长度。但是，上面显示的代码会在所有中返回 no 输出，并且我已经在这个问题上工作了三天。

我无法看到是阻止我的代码产生所需的输出？

Answer 1

在这个循环中

a = 1;                                          //reset the array_position to one
do{
    if(y[a] > 0){                               //if current array_position holds a value greater than 0
        printf("%i",a);                         //print the name of the array_position (1,2,3...)
        for(d = 0; d < y[a]; ++d){              //reset the word_length--if the word_length is less than the value contained in the current array position, increment the word length by one
            putchar('-');                       //print a dash and re-evaluate the condition
        }
        if(d == y[a]){                          //when the word_length is equal to the value contained in the current array position
            putchar('-');                       //print a final dash
            putchar('\n');                      //and a newline
        }
    }
    ++a;                                        //increment the array position by one
}while(a > 11);

您需要检查while (a < 11)而不是while (a > 11)

并且，（正如@WeatherVane指出的那样）：

if(c != ' ' && c != '\n' && c != '\t')      //if c is anything other than a blank, newline or tab
    ++b;                                     //increment the word_length by one
else                                        //otherwise
    ++a;                                    //increment the array_position by one
    b = 0;

看起来很可疑，你是否忘记了第二个街区附近的牙箍？

if(c != ' ' && c != '\n' && c != '\t')      //if c is anything other than a blank, newline or tab
    ++b;                                     //increment the word_length by one
else {                                       //otherwise
    ++a;                                    //increment the array_position by one
    b = 0; 
}

Answer 2

两个主要问题：

首先，如前所述，您的do..while循环应检查a < 11而不是a > 11。

第二个问题出现在您的第一个for循环中：

for(y[a] = 0; (c = getchar()) != EOF;){     
    if(c != ' ' && c != '\n' && c != '\t')  
        ++b;                                
    else                                    
        ++a;                                
        b = 0;                              
}

除了else部分周围缺少大括号之外，当你第一次进入循环时，除了位置1之外，你永远不会为y的元素赋值。

您需要将数组元素初始化为0，然后需要增加y[b]而不是a：

for (d=0;d<10;d++) {
    y[d] = 0;
}
while ((c = getchar()) != EOF) {
    if(c != ' ' && c != '\n' && c != '\t') {
        ++b;                                
    } else {
        ++y[b];
        b = 0;    
    }                          
}

C字计数直方图应用程序不返回任何输出

2 个答案: