Lecture 16 Word Count Solution

Joseph Haugh

University of New Mexico

Count Lines of Input

Book Version:

void main(void) {
  int c;
  int numberOfLines = 0;

  while((c = getchar()) != EOF) {
    if(c == '\n') numberOfLines++;
  }

  printf("%d\n", numberOfLines);
}
  1. Read a character from stdin
  2. Copies character to c
  3. Compares c to EOF

Count Lines of Input

Modified Version:

void main(void) {
  int numberOfLines = 0;
  int c = getchar();

  while(c != EOF) {
    if(c == '\n') numberOfLines++;
    c = getchar();
  }
  printf("%d\n", numberOfLines);
}

Why is getchar called twice?

Count Characters, Lines, and Words 1.5.4

#define IN 1
#define OUT 0
void main(void) { 
  int c, nl, nw, nc, state;
  state = OUT;
  nl = nw = nc = 0;
  while((c = getchar()) != EOF) {
    ++nc;
    if (c == '\n') ++nl;
    if(c == ' ' || c == '\n' || c == '\t')
      state = OUT;
    else if(state == OUT) {
      state = IN;
      ++nw;
    }
  }
  printf("%d %d %d\n", nl, nw, nc);
}

Coding style in textbook:

  • Variable names are too short
  • Multiple actions in one line
  • Leaves out braces

Counting it all – Top Level

#define IN 1
#define OUT 0 
 
void main(void) {
  /* Body of function on next slides */
}

Counting it all – Main

void main(void) {
  int charCount = 0;
  int totalCharCount = 0;
  int wordCount = 0;
  int totalWordCount = 0;
  int wordState = OUT;
  int lineCount = 1;
  int c = getchar(); 

  while (c != EOF) {
    /* BODY ON NEXT SLIDE */
  }
  printf("%d lines, %d words, %d characters\n",
         lineCount-1, totalWordCount, totalCharCount);
}

Counting it all – While Body

  if (charCount == 0) { 
    printf("(%2d) ", lineCount);
  }  
  if (c == '\n') {
    printf("[%d, %d]\n", wordCount, charCount);
    charCount = 0;
    wordCount = 0;
    wordState = OUT;
    lineCount++;
  }
  else {
      /* BODY ON NEXT SLIDE */
  }

Counting it all – While Body

  else { /* char just read not '\n' */
    charCount++;
    totalCharCount++;
    printf("%c", c);
    if (c == ' ' || c == '\n' || c == '\t') { 
      wordState = OUT;
    }
    else if (wordState == OUT) {
      wordState = IN;
      wordCount++;
      totalWordCount++;
    }
  } 
  c = getchar();

Finding Longest Lines

Add some variables to track with:

int mostCharLineNum = 0;
int mostCharCount = 0;
int mostWordLineNum = 0;
int mostWordCount = 0;

Output the results at the end:

printf("%d lines, %d words, %d characters\n",
         lineCount-1, totalWordCount, totalCharCount);
printf("Line %d has the most words with %d\n",
        mostWordLineNum, mostWordCount);
printf("Line %d has the most characters with %d\n",
        mostCharLineNum, mostCharCount);

Finding Longest Lines

At the end of lines, check for new longest line:

  if (c == '\n') {
    printf("[%d, %d]\n", wordCount, charCount);
    if(charCount > mostCharCount) {
        mostCharCount = charCount;
        mostCharLineNum = lineCount;
    }
    if(wordCount > mostWordCount) {
        mostWordCount = wordCount;
        mostWordLineNum = lineCount;
    }            
    charCount = 0;
    wordCount = 0;
    wordState = OUT;
    lineCount++;
  }
  else {