How to only print a to z in C

Question

I am trying to make my histogram print only a to z and not spaces or other symbols. From my code below how could I achieve this. I have set c to ignore case but i cannot figure out how to ignore white spaces and etc.

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#define READ 5000

main() {
    int c;
    int i;
    int x;
    int length[READ];
    {
        for (x = 0; x < READ; x++)
            length[x] = 0;
        while ((c = getchar()) != EOF) {
            c = tolower(c); // ignores all cases.
            length[c]++;
            if (c == EOF)
                break;
        }
    }
    for (x = 0; x < READ; x++) {
        if (length[x] > 0) {
            printf("%c| ", x);
            for (i = 1; i <= length[x] / 5; ++i) {
                // since the value i is int when a value less than 5
                // such as 4/5 appears as   0. 5/5 to 9/5 is 1 "x"
                printf("X"); // prints an X for every 5 of a character
            }
            printf("\b\b\b\b\b\t\t\t(%d)", length[x]);
            printf("\n"); // aligns the histogram with new line
        }
    }
}

Perhaps an `if (isalpha(c))` (or `if (!isalpha(c))`, depending) would help? — Jerry Coffin, Sep 11 '14 at 18:56
C and C++ are not the same language, and in many cases, the "natural" answer for one may not work in the other language. Pick the one you are working with and tag only that language. — crashmstr, Sep 11 '14 at 18:58
Note that there are only 256 byte values, so 5000 is serious overkill (almost 20 times longer than needed). — Jonathan Leffler, Sep 11 '14 at 19:08

John Hascall · Answer 1 · 2014-09-11T19:17:15.113

0

Not 100% sure what you are looking for, but perhaps:

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

  int main ( void ) {
     int c;
     int i;
     int x;
     int n;  
     int count[26];
     int N = (sizeof(count)/sizeof(count[0]));

     for(x = 0; x < N; x++) count[x] = 0;
     while ((c = getchar() ) != EOF) {
        if (!isalpha(c)) continue;
        i = tolower(c) - 'a';
        count[i]++;
     }
     for (x = 0; x < N; x++) {
        if (count[x] == 0) continue;
        printf("%c| ", x + 'a');
        n = count[x]/5;
        for(i = 1; i <= n; ++i) printf("X");
        printf(" %*s(%d)\n", 50 - n, "", count[x]);
     }
     return 0;
}

NOTE: most probably will not work on other than US ascii.

edited Sep 11 '14 at 19:17

answered Sep 11 '14 at 19:11

John Hascall

9,176
6
48
72

1

To be more general, use `count[256]`, and omit the `- 'a'` and `+ 'a'` parts. – John Hascall Sep 11 '14 at 19:19
"NOTE: most probably will not work on other than US ascii." So, don't perpetuate the _myth that ASCII is being used_. It is reasonable to assume that a `char` is 8 bits and therefore there are 256 `char` values. – Tom Blodget Sep 11 '14 at 23:08

score 0 · Answer 2 · answered Sep 11 '14 at 19:25

The isalpha() is the best place to start to filter out non-alpha char.

Use #define READ (UCHAR_MAX + 1)

   while ((c = getchar()) != EOF) {
     if (isalpha(c) {
       c = tolower(c);
       length[c]++;
     }
   }

To deal with printing the histogram, use the return value from printf() as it reports the number of char printed to calcualte the offset. Use "%*s" to print the needed spacer.

for (x = 0; x < READ; x++) {
  int maxoffset = 0;
  if (length[x] > 0) {
    char buffer[100];
    int offset = sprintf(buffer, "%c| ", x);
    for (i = 1; i <= length[x] / 5; ++i) {
      offset += printf("X"); // prints an X for every 5 of a character
    }
    // Print length on the 40th column
    offset = 40 - offset;
    if (offset <= 0) offset = 1;
    printf("%*s(%d)\n", offset, "", length[x]);
  }

How to only print a to z in C

2 Answers2