[Nâng cao] Tìm kiếm chuỗi trong chuỗi - Lập trình C

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char *argv[]) {
	//khai bao 2 chuoi
	char s1[50], s2[50];
	
	//Nhap du lieu
	printf("\nNhap s1 = ");
	gets(s1);
	printf("\nNhap s2 = ");
	gets(s2);
	
	//giai thuat tim kiem
	int i, j, length1, length2;
	length1 = strlen(s1);
	length2 = strlen(s2);
	bool isFind;
	
	if(length1 >= length2) {
		for(i=0;i<=length1-length2;i++) {
			isFind = true;
			for(j=0;j<length2;j++) {
				if(s1[i+j] != s2[j]) {
					isFind = false;
					break;
				}
			}
			if(isFind) {
				printf("\nVi tri tim thay = %d", i);
			}
		}
	} else {
		//do dai s2 > doi dai s1 -> khong tim thay
		printf("\nChuoi nhap vao ko hop le!!!");
	}
	
	return 0;
}