What’s wrong with this 1988 C code?

by

Your problem is with your preprocessor definitions of IN and OUT:

#define IN   1;     /* inside a word */
#define OUT  0;     /* outside a word */

Notice how you have a trailing semicolon in each of these. When the preprocessor expands them, your code will look roughly like:

    if (c == ' ' || c == '\n' || c == '\t')
        state = 0;; /* <--PROBLEM #1 */
    else if (state == 0;) { /* <--PROBLEM #2 */
        state = 1;;

That second semicolon causes the else to have no previous if as a match, because you are not using braces. So, remove the semicolons from the preprocessor definitions of IN and OUT.

The lesson learned here is that preprocessor statements do not have to end with a semicolon.

Also, you should always use braces!

    if (c == ' ' || c == '\n' || c == '\t') {
        state = OUT;
    } else if (state == OUT) {
        state = IN;
        ++nw;
    }

There is no hanging-else ambiguity in the above code.

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