C 언어로 string Replace 함수 만들기 (2)

C 언어로 string Replace 함수 만들기 2 번 째 방법이다.

/*
  https://www.geeksforgeeks.org/c-program-replace-word-text-another-given-word/
*/


// C program to search and replace
// all occurrences of a word with
// other word.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

// Function to replace a string with another
// string
char* replaceWord(const char* s, const char* oldW,
				const char* newW)
{
	char* result;
	int i, cnt = 0;
	int newWlen = strlen(newW);
	int oldWlen = strlen(oldW);

	// Counting the number of times old word
	// occur in the string
	for (i = 0; s[i] != '\0'; i++) {
		if (strstr(&s[i], oldW) == &s[i]) {
			cnt++;

			// Jumping to index after the old word.
			i += oldWlen - 1;
		}
	}

	// Making new string of enough length
	result = (char*)malloc(i + cnt * (newWlen - oldWlen) + 1);

	i = 0;
	while (*s) {
		// compare the substring with the result
		if (strstr(s, oldW) == s) {
			strcpy(&result[i], newW);
			i += newWlen;
			s += oldWlen;
		}
		else
			result[i++] = *s++;
	}

	result[i] = '\0';
	return result;
}

// Driver Program
int main()
{
	char str[] = "xxforxx xx for xx";
	char c[] = "xx";
	char d[] = "Geeks";

	char* result = NULL;

	// oldW string
	printf("Old string: %s\n", str);

	result = replaceWord(str, c, d);
	printf("New String: %s\n", result);

	free(result);
	return 0;
}