a few doubts!

#include<stdio.h>
#include<conio.h>
#include<string.h>
main()
{
char * a= "bcd";
clrscr();
strcpy(a,"hello");
a = "fgh";
a[0] = 't';
printf("%s",a);
}


now, in TC there is absolutely no error .....i thought it
should........coz' when i declare a as a char * and assign it to some
string then it should be a constant and cannot do things like a[0] = '4'
and stuff........infact the entire thing here works properly....so why
should it work properly??


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