#include<string.h>
main()
{
    char s1[50],s2[50];
    printf("enter string 1\n");
    gets(s1);
    printf("enter string 2\n");
    gets(s2);
    strcat(s1,s2);
    printf("the Concatenate string is");
    puts(s1);
}


     
           
Note: Need to be arranged in compiler after copied
   

 OutPut:

enter string 1 Hello enter string 2 World the Concatenate string is HelloWorld