#include <iostream>
#include <cstring>
using namespace std;
int main()
{
char s1[10] = "Hello";
cout << strlen(s1) << endl;
char s2[50];
strcpy(s2, s1);
cout << s2 << endl;
char s3[10] = "World";
strcat(s2, s3);
cout << s2 << endl;
char s4[50] = "HelloWorld";
if (strcmp(s2, s4) == 0)
cout << "true" << endl;
else
cout << "false" << endl;
char s5[30];
strncpy(s5, s4, 5);
cout << s5 << endl;
char target[10] = "Hello";
if (strstr(s4, target) != NULL)
cout << "true" << endl;
else
cout << "false" << endl;
return 0;
}