Определить, является ли одна строка символов - частью другой

#include <iostream>
using namespace std;
int main()
{
const int size=9;
char *hr=new char[size];
char *rh=new char[size];
        cin>>hr;
        cin>>rh;
            for(int j=0;j<size;++j)
            {
    if(hr[j]!=rh[j])
    {cout<<"error";}
    else
    cout<<"one string is the part of another"<<endl;
            }
}

#include <string>
#include <iostream>
using namespace std;
 
bool isSubInStr(const char * str, const char * fnd);
 
int main()
{
    char str[] = "This is input text as test";
    char fnd1[] = "text";
    char fnd2[] = "find";
    cout<<"Input string : \n"<<str<<endl;
    cout<<"Str1 for find: "<<fnd1<<" : "<<(isSubInStr(str, fnd1) ? "is present in text" : "is absent in text")<<endl;
    cout<<"Str2 for find: "<<fnd2<<" : "<<(isSubInStr(str, fnd2) ? "is present in text" : "is absent in text")<<endl;
    return 0;
}
 
bool isSubInStr(const char * str, const char * fnd)
{
    bool bExist = false;
    if(str && fnd)
        bExist = strstr(str, fnd) != 0;
    return bExist;
}

#include <string>
#include <iostream>
using namespace std;
 
bool isSubInStr(string str, string fnd);
 
int main()
{
    string str = "This is input text as test";
    string fnd1 = "text";
    string fnd2 = "find";
    cout<<"Input string : \n"<<str<<endl;
    cout<<"Str1 for find: "<<fnd1<<" : "<<(isSubInStr(str, fnd1) ? "is present in text" : "is absent in text")<<endl;
    cout<<"Str2 for find: "<<fnd2<<" : "<<(isSubInStr(str, fnd2) ? "is present in text" : "is absent in text")<<endl;
    return 0;
}
 
bool isSubInStr(string str, string fnd)
{
    bool bExist = false;
    if(str.length() && fnd.length())
        bExist = str.find(fnd, 0) != string::npos;
    return bExist;
}

#include <iostream>
using namespace std;
 
bool isSubInStr(const char * str, const char * fnd);
 
int main()
{
    char str[] = "This is input text as test";
    char fnd1[] = "text";
    char fnd2[] = "find";
    cout<<"Input string : \n"<<str<<endl;
    cout<<"Str1 for find: "<<fnd1<<" : "<<(isSubInStr(str, fnd1) ? "is present in text" : "is absent in text")<<endl;
    cout<<"Str2 for find: "<<fnd2<<" : "<<(isSubInStr(str, fnd2) ? "is present in text" : "is absent in text")<<endl;
    return 0;
}
 
bool isSubInStr(const char * str, const char * fnd)
{
    int i, j;
    bool bExist = false;
    for(i = 0; str[i]; i++)
    {
        bExist = false;
        for(j = 0; fnd[j] && str[i + j]; j++)
        {
            bExist = fnd[j] == str[i + j];
            if(!bExist)
                break;
        }
        bExist = (str[i] == fnd[i]);
        if(bExist)
            break;
    }
    return bExist;
}