Question

我试图用C编写一个程序来打印通过getchar（）输入的单词长度。这是代码：

#include<stdio.h>

#define IN 1
#define OUT 0

int main()
{
int c, chars, state, i;
int nlength[20];

state = OUT;
chars = 0;

for (i = 0; i < 20; ++i){
   nlength[i] = 0;
}


while ((c = getchar()) != EOF){
     if (c != ' ' && c != '\t' && c != '\n'){
        state = IN;
        ++chars;
     }

     else if (state == OUT){
             ++nlength[chars];
             chars = 0;
     }
}
if (c == EOF){
  ++nlength[chars];
}  

printf("\nLength of words = ");

for (i = 0; i < 20; ++i){
   printf(" %d", nlength[i]);
}

printf("\n");
}

它应该输出，例如输入＆＃34; aaa aaa＆＃34;，：0 0 0 2 0 0 0 .... 但是，它会输出类似0 0 0 0 0 0 1 0 0 ...的内容。有谁能告诉我它有什么问题？

Answer 1

在您的代码中state永远不会更改为OUT，因此以下行：

 else if (state == OUT){
         ++nlength[chars];
         chars = 0;
 }

永远不会被执行。

还有一些地方看起来很可疑。例如。你永远不会检查阵列边界。此外，您不需要state变量，只需检查chars > 0。

以下是您的代码，但有一些修改：

#include <stdio.h>
// we can use isspace function from ctype.h
#include <ctype.h>

#define MAX_LEN 20

int main() {
  int c;
  int chars = 0;
  // this way we don't have to zero the array explicitly
  int nlength[MAX_LEN] = {0};

  while ((c = getchar()) != EOF) {
    if (!isspace(c))
      ++chars;
    else {
      // if chars == 0 we increment nlength[0]
      // which is not used anyway
      if (chars < MAX_LEN)
        ++nlength[chars];
      chars = 0;
    }
  }

  // if chars == 0 we increment nlength[0]
  if (chars < MAX_LEN)
    ++nlength[chars];

  // set 0-length words element to zero
  nlength[0] = 0;

  printf("\nLength of words = ");

  for (int i = 0; i < MAX_LEN; ++i) {
    printf(" %d", nlength[i]);
  }

  printf("\n");
}

来自getchar（）的单词长度

1 个答案: