C language programming exercise reference answer chapter 7 (2) pointer and array main function parameters

/* 7.16 implement the strlen () function for testing the string length ()*/
# Include "stdio. H"
Int strlen (char * P );
Void main ()
{
Char S1 [20] = "s1s2s3s4 ";
Char * P = S1;
Printf ("S1 length: % d \ n", strlen (S1 ));
Printf ("S1 length: % d \ n", strlen (p ));
Printf ("length of the string ABC123: % d \ n", strlen ("ABC123 "));
}

Int strlen (char * P)
{
Int length = 0;
While (* P! = '\ 0 ')
{
Length ++;
P ++;
}
Return length;
}
/* 7.19 The pointer array is used as the main function parameter. Note: According to the exercise requirements, this file must be named welcome. C */
# Include "stdio. H"
Void main (INT argc, char * argv [])
{
Int I;
Printf ("Welcome to you ");
For (I = 1; I <argc; I ++)
Printf ("% s", argv [I]);
}