C++ program to concatenate two strings

C++ program to concatenate two strings. Here I given five program to concatenate two string like using strcat() function ,without using strcat() function, using pointers ,using recursion, using operator overloading.

C++ program to concatenate two strings without using strcat() function

#include<iostream>
#include<conio.h>
#include<string.h>
using namespace std;
int main()
{
    char str1[20],str2[20];
    int lenght,i;
    cout<<"Enter two String : ";
    cin>>str1>>str2;
    lenght=strlen(str1);
    for(i=lenght;str2[i-lenght]!='\0';i++)
        str1[i]=str2[i-lenght];
        str1[i]='\0';
    cout<<"After concatenating : "<<str1;
    return 0;
}

C++ program to concatenate two strings using strcat() function

#include<iostream>
#include<conio.h>
#include<string.h>
using namespace std;
int main()
{
    char str1[20],str2[20];
    cout<<"Enter two String : ";
    cin>>str1>>str2;
    strcat(str1,str2);
    cout<<"After concatenating : "<<str1;
    return 0;
}

C++ program to concatenate two strings using pointers

#include<iostream>
#include<string.h>
using namespace std;
int main()
{
    char str1[20],str2[20],*p,*q;
    cout<<"Enter two string : ";
    cin>>str1>>str2;
    p=str2;
    q=&str1[strlen(str1)];
    while(*p!='\0')
    {
        *q=*p;
        q++,p++;
    }
    *q='\0';
    cout<<"After concatenating string : "<<str1;
    return 0;
}

C++ program to concatenate two strings using recursion

#include<iostream>
#include<string.h>
using namespace std;
void catstr(char *str1,char *str2,int length,int i)
{
    if(str2[i-length]==0)
    {
        str1[i]='\0';
        return;
    }
    str1[i]=str2[i-length];
    catstr(str1,str2,length,i+1);
}
int main()
{
    char str1[20],str2[20];
    int length,i;
    cout<<"Enter two String : ";
    cin>>str1>>str2;
    length=strlen(str1);
    catstr(str1,str2,length,length);
    cout<<"After concatenating : "<<str1;
    return 0;
}

C++ program to concatenate two strings using operator overloading

#include<iostream>
#include<conio.h>
#include<string.h>
using namespace std;
struct cat
{
    char str[20];
};
cat operator+(cat a,cat b)
{
    int i,lenght=strlen(a.str);
    for(i=lenght;b.str[i-lenght]!='\0';i++)
        a.str[i]=b.str[i-lenght];
        a.str[i]='\0';
    return a;
}
int main()
{
    cat a,b;
    int lenght,i;
    cout<<"Enter two String : ";
    cin>>a.str>>b.str;
    a=a+b;
    cout<<"After concatenating : "<<a.str;
    return 0;
}