#include <stdio.h>
#include <string.h>
int main()
{
    char a[20], b[20];
    printf("———————————————————————————————————————————");
    printf("\nProgram to concatenate the two strings");
    printf("\n———————————————————————————————————————————");
    printf("\nEnter the 1st string ");
    scanf("%s", a);
    printf("\nEnter the 2nd string ");
    scanf("%s", b);
    strcat(a, b);
    printf("\nThe concatenated string is %s", a);
    printf("\n———————————————————————————————————————————\n");
    return 0;
}

kodingwindow@kw:~$ gcc kw.c
kodingwindow@kw:~$ ./a.out
———————————————————————————————————————————
Program to concatenate the two strings
———————————————————————————————————————————
Enter the 1st string KODING

Enter the 2nd string WINDOW

The concatenated string is KODINGWINDOW
———————————————————————————————————————————
kodingwindow@kw:~$