C++ program to perform string concatenation:

StringClass2.cpp

    

#include<iostream>
    #include<cstring>
    using namespace std;
    class sstring{
        char* s;
        int len;
        public:
            sstring();
            sstring(char *a);
            void concat(sstring x,sstring y);
            void display();
    };
    sstring::sstring(){
        len=0;
        s=new char[len+1];
    }
    sstring::sstring(char *a){
        len=strlen(a);
        s=new char[len+1];
        strcpy(s,a);
    }
    void sstring::concat(sstring x,sstring y){
        len=x.len+y.len;
        s=new char[len+1];
        strcpy(s,x.s);
        strcat(s," ");
        strcat(s,y.s);
    }
    void sstring::display(){
        cout<<"\nThe string is "<<s<<endl;
    }
    int main()
    {
        char x[100];
        cout<<"Enter the first string ";
        cin>>x;
        sstring a(x);
        cout<<"\nEnter the second string ";
        cin>>x;
        sstring b(x);
        sstring c;
        c.concat(a,b);
        c.display();
        return 0;
    }