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Phrase reversals: Difference between revisions
C solution addition
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word-order reversed : Reversal Phrase Code Rosetta
each word reversed : attesoR edoC esarhP lasreveR
</pre>
=={{header|C}}==
Working with C strings is often long-winded.
<lang C>
#include <stdio.h>
#include <string.h>
/* The functions used are destructive, so after each call the string needs
* to be copied over again. One could easily allocate new strings as
* required, but this way allows the caller to manage memory themselves */
char* reverse_section(char *s, size_t length)
{
if (length == 0) return s;
size_t i; char temp;
for (i = 0; i < length / 2 + 1; ++i)
temp = s[i], s[i] = s[length - i], s[length - i] = temp;
return s;
}
char* reverse_words_in_order(char *s, char delim)
{
if (!strlen(s)) return s;
size_t i, j;
for (i = 0; i < strlen(s) - 1; ++i) {
for (j = 0; s[i + j] != 0 && s[i + j] != delim; ++j)
;
reverse_section(s + i, j - 1);
s += j;
}
return s;
}
char* reverse_string(char *s)
{
return strlen(s) ? reverse_section(s, strlen(s) - 1) : s;
}
char* reverse_order_of_words(char *s, char delim)
{
reverse_string(s);
reverse_words_in_order(s, delim);
return s;
}
int main(void)
{
char str[] = "rosetta code phrase reversal";
size_t lenstr = sizeof(str) / sizeof(str[0]);
char scopy[lenstr];
char delim = ' ';
/* Original String */
printf("Original: \"%s\"\n", str);
/* Reversed string */
strncpy(scopy, str, lenstr);
reverse_string(scopy);
printf("Reversed: \"%s\"\n", scopy);
/* Reversed words in string */
strncpy(scopy, str, lenstr);
reverse_words_in_order(scopy, delim);
printf("Reversed words: \"%s\"\n", scopy);
/* Reversed order of words in string */
strncpy(scopy, str, lenstr);
reverse_order_of_words(scopy, delim);
printf("Reversed order: \"%s\"\n", scopy);
return 0;
}
</lang>
{{Out}}
<pre>
Original: "rosetta code phrase reversal"
Reversed: "lasrever esarhp edoc attesor"
Reversed words: "attesor edoc esarhp lasrever"
Reversed order: "reversal phrase code rosetta"
</pre>
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