#include <stdio.h>
/* strws.c - string function to replace blanks and tabs
* with a single blank. */
char *strws(char *str)
{
char *from = str; /* pointer to destination */
char *to = str; /* pointer to source */
if (str != NULL) {
/* copy characters looking for a blank or a tab. */
while (*from) {
if (*from == ' '|| *from == '\t') {
/* if blank or tab is found, copy one blank to
* the destination and skip any other blanks or
* tabs after the one we found. */
*to++ = ' '; from++;
while (*from)
if (*from != ' ' && *from != '\t')
break;
else
from++;
}
/* whether we found a blank (or tab) above or not,
* we are not pointing to one now, so copy the
* character we are pointing to and continue. */
*to++ = *from++;
}
*to = '\0'; /* terminate new string */
}
return str;
} /*strws*/
#ifdef TESTMAIN
#define MAXSIZE 1024
int errors = 0; /* count of errors encountered */
char *rv; /* value returned by call to strws */
char buf[MAXSIZE]; /* buffer to hold result of each test case */
int testcase = 0; /* test case counter */
/* testin contains a list of test cases */
char *testin[] = {
"This has no extra white space ",
" ",
"This \t has\t \ta\tmixture\t \t \t \t",
"\tLeading and trailing tab\t",
"\t\t\t\tLeading and trailing tabs\t\t\t\t",
" Leading and \ttrailing blanks ",
""
};
/* testout contains the expected result of sending the corresponding
* element in testin to strws. */
char *testout[] = {
"This has no extra white space ",
" ",
"This has a mixture ",
" Leading and trailing tab ",
" Leading and trailing tabs ",
" Leading and trailing blanks ",
""
};
main()
{
printf("strws test: starting\n");
if ((rv = strws((char *) 0)) != NULL)
{
printf("ERROR 1: strws(NULL) returned %p\n",rv);
printf(" expected NULL\n");
errors++;
}
do {
/* make a copy of a test case */
strcpy(buf, testin[testcase]);
/* run the test and see if strws returns a pointer to
* the beginning of the atring as it should. */
if ((rv = strws(buf)) != buf) {
printf("ERROR 2: case %d:strws(%s)\nreturned %p\n",
testcase, bur, rv);
errors++;
}
/* see if the result obtained is the same as the expected
* result. */
if (strcmp(buf, testout[testcase]) != 0) {
printf("ERROR 3: case %d:strws(%s)", testcase,
testin[testcase]);
printf(" returned [%s]\n", buf);
printf(" expected [%s]\n", testout[testcase]);
errors++;
}
} while {testin[testcase++][0] != 0);
if (errors)
printf("strws: Failed, %d errors encountered.\n", errors);
else
printf("strws: SUCCEEDED\n");
return 0;
} /*main*/
#endif
/* End of File */