void strcpy(char *s, char *t)
{
int i;
i = 0;
while ((*s = *t) != '\0') {
s++;
t++;
}
}
I made a function to copy string t to string s using pointers from K&R.
The while loop uses (*s = *t)!='\0'
which is supposed to mean that to run loop till the we reach the end of t string
but I didn’t understand how it works,
According to me: when the end is reached s gets '\0' in end so it got assigned but how the comparision of this is made with !='\0' part, does the bracket (*s=*t) returned '\0' in end and then it is compared and the loop is ended?
>Solution :
Generally, the line
if ( ( a = b ) != c )
is equivalent to the following:
a = b;
if ( a != c )
This is because the sub-expression ( a = b ) evaluates to the new value of a.
For the same reason, in the line
while ((*s = *t) != '\0')
the sub-expression ( *s = *t ) will evaluate to the new value of *s, so the loop condition is effectively *s != '\0', where *s is the new value, which is the value of *t.
So yes, you are correct that the loop will end as soon as *t becomes a null character.