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Do
not award half marks. Do not deduct marks for trivial syntactic errors.
Alternative correct answers should be given credit, unless otherwise
indicated in the marking scheme.
(a)Write a function,called
Copy the signature of which is given below,which will copy at most
n characters from the string src into the string dst You may assume
that dst is a character string with at least n+1 elements.
void Copy(const char* src, char* dst, int n); [5 marks ]
A sample definition
of Copy follows:
void Copy(const char* src, char* dst, int n)
{
while( *src != ’\0’ &&n >0){
*(dst)++ = *(src)++;
n--;
}
*dst= ’\0’;
}
And the following marking scheme shouldbe used:
•Declaring a suitable iterative structure;(1 mark)
•Bound by the length of the source string and n(1 mark)
•Copying
the appropriate character on each iteration,and incrementing the string
pointers appropriately;(1 mark)
•Decrementing n on each iteration;(1 mark)
•Ensuring that the destination string is NULL terminated after
all characters have been copied.(1 mark)
[5 marks ]
(b)Write a function,called IsMember the
signature of which is given below which will return a pointer to the
first instance of the character c in the string s If there is no occurrence
of the character in the string,then the function should return NULL
char* IsMember(char* s, char c); [5 marks ]
A sample definition
of IsMember follows:
char* IsMember(const char* s, char c)
{
char* t= s;
while((*t)!= ’\0’) {
if ((*t) ==c ){
return t;
}
t++;
}
return NULL;
}
And the following marking scheme shouldbe used:
•Declaring a suitable iterative structure;(1 mark)
•Bound by the length of the string;(1 mark)
•Correctly comparing the character in the string with the test
character,with the correct de-referencing;(1 mark)
•Returning t when a match is found,NULL if the endof the string
has been found without a match;(1 mark)
•Incrementing the local string pointer on each iteration.(1 mark)
[5 marks ]
(c)Write
a function,called RemoveMember the signature of which is given below,which
will take a string s and return a reference to the string with all
occurrences of the character c removed from the string.For example,calling
the function on the string abcabcabc with the character a to be removed
wouldresult in the string bcbcbc.
void RemoveMember(char* s, char c); [5 marks ]
A sample definition
of RemoveMember follows:
void RemoveMember(char* s, char c)
{
int i, j;
i= 0; j= i+1;
for(i= 0; i< sizeof(s); i++)
if(s[i]== c)
for(j= i; j< sizeof(s);
j++)
s[j]= s[j+1];
}
And the following marking scheme shouldbe used:
•Declaring a loo to iterate over the source string;(1 mark)
•Correctly bound by the length of the string (1 mark)
•Comparing the current character on each iteration with c(1 mark)
Declaring a loop to iterate over the remainder of the string if a
match is found; (1 mark)
•Copying the j+1th character into the jth position whilst looping
over the
string.(1 mark)
[5 marks ]
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