Program in C to concatenate two strings

Write a program in C to concatenate two strings

#include <stdio.h>

void main ()

{

            char *str,*str1;

            clrscr ();

            printf("Enter your name: ");

            gets (str);

            str1="jeet";

            strcat(str,str1);

            printf("\n %s",str);

            getch ();

}