c - fill word with blanks -
i have following code strange chars instead of blanks:
char *getword(const char *string) { char *chars = "-_"; int len = 0; int max = 10; char *res = malloc(max + 1); ( ; len<max; string++) { if(*string) { if (!strchr(chars, *string)) { res[len] = *string; ++ len; } } else { res[len] = ' '; ++ len; } } res[len] = 0; return res; } ex: char *mystring = "my-str_a"; //the result want be: "mystra" followed 4 blanks: "mystra "
how can fill blanks end of word until reaches max length ?
original answer
one problem missing else clause if (*string), need set character blank. problem read past end of string.
char *getword(const char *string) { char *chars = "-_"; int max = 10; int len; char *res = malloc(max + 1); if (res == 0) return res; (len = 0; len < max; len++) { if (*string) { if (!strchr(chars, *string)) res[len] = *string; else res[len] = ' '; string++; } else res[len] = ' '; } res[len] = 0; return res; } this uses conventional for (int len = 0; len < max; len++) loop step through allocated array. code increments string when not pointing @ terminal null byte. there assignment res[len] on each iteration. code checks memory allocation succeeds — important in real programs.
revised answer
the function getword2() require. note test harness.
#include <assert.h> #include <stdio.h> #include <stdlib.h> #include <string.h> static char *getword1(const char *string) { char *chars = "-_"; int max = 10; int len; char *res = malloc(max + 1); if (res == 0) return res; (len = 0; len < max; len++) { if (*string) { if (!strchr(chars, *string)) res[len] = *string; else res[len] = ' '; string++; } else res[len] = ' '; } res[len] = 0; return res; } static char *getword2(const char *string) { char *chars = "-_"; int max = 10; int len = 0; char *res = malloc(max + 1); if (res == 0) return res; while (len < max) { if (*string) { if (!strchr(chars, *string)) res[len++] = *string; string++; } else res[len++] = ' '; } res[len] = 0; return res; } int main(void) { const char *data[] = { "my-str_a", "--m--__", "my str a", "abyssinianelephant", "--m--__m--m--m-m-m-m-m-m-m-m-m-m", }; (size_t = 0; < sizeof(data)/sizeof(data[0]); i++) { char *res1 = getword1(data[i]); char *res2 = getword2(data[i]); char source[30]; snprintf(source, sizeof(source), "<<%.25s>>", data[i]); assert(res1 != 0 && res2 != 0); // reprehensible! printf("%-30.30s --> <<%s>> or <<%s>>\n", source, res1, res2); free(res1); free(res2); } return 0; } sample output:
<<my-str_a>> --> <<my str >> or <<mystra >> <<--m--__>> --> << m >> or <<m >> <<my str a>> --> <<my str >> or <<my str >> <<abyssinianelephant>> --> <<abyssinian>> or <<abyssinian>> <<--m--__m--m--m-m-m-m-m-m->> --> << m m >> or <<mmmmmmmmmm>> if 'mmmmmmmmmm' output isn't want, specification needs tightening bit. tweaks aren't hard, need specified.
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