Thay_The_Chuoi.cpp

// Thay_The_Chuoi.cpp
#include <iostream>
#include <string.h>

using namespace std;

void xoaKyTu(char str[255], int k) {
	for (int i = k; i < strlen(str); i++)
		str[i] = str[i+1];
}

void chenKyTu(char str[255], char x, int k) {
	int n = strlen(str);
	for (int i = n; i > k ; i--)
		str[i] = str[i-1];
	str[k] = x;
	str[n+1] = '\0';
}

void thayTheChuoi(char inputStr[255], char findStr[255], char replaceStr[255]) {
	bool find_ok = false;
	for (int i = 0; i < strlen(inputStr); i++) {
		for (int j = 0; j < strlen(findStr); j++) {
			if (inputStr[i+j] != findStr[j]) {
				find_ok = false;
				break;
			}
			find_ok = true;
		}
		if (find_ok) {
			for (int k = 0; k < strlen(findStr); k++) {
				xoaKyTu(inputStr, i);
			}
			for (int k = 0; k < strlen(replaceStr); k++) {
				chenKyTu(inputStr, replaceStr[k], i + k);
			}
		}
	}
}

int main() {
	char str[255];
	cout<<"Nhap str: "; fflush(stdin); gets(str);
	char timKiem[] = "child";
	char thayThe[] = "children";
	thayTheChuoi(str, timKiem, thayThe);
	cout<<"Chuoi sau khi thay the: "<<str<<endl;
	return 0;
}