Strpbrk function

[pacman169]

Any idea how would I test this thing?

 char * strbrk( char *s1, char *s2)

{

    char c;
    
    while ((*s1++ = c) != 0)
    {
      for( ; *s2 != 0 ; ++s2 )
            if ( s2 == c)
               return (char *) s1;
    }
    
    return (NULL);

 }
 
 
 

[MiiNiPaa]

You pass it several pairs of strings and see if result is expected one.

[pacman169]

What do you mean exactly? Do I need to print a pointer?
If I knew how to test it I would have probably already did that.

[MiiNiPaa]

Ok, lets start from the beginning.
What this function does? How do you want/expect to use it in your code?

[andywestken]

Test code.

I tweaked your (rather broken!) code so it built, but it's only passing 1 out of 4 test cases (and still need more test cases.)

TestCase #1
s1 = abc
s2 = a
p = NULL
- fail!

TestCase #2
s1 = abc
s2 = b
p = NULL
- fail!

TestCase #3
s1 = abc
s2 = c
p = NULL
- fail!

TestCase #4
s1 = abc
s2 = d
p = NULL
- pass!

Passed 1 out of 4 test cases.

It worked with these tests after 5 or so changes (depending on how you define a code change.)

Andy

// strbrk test

#include <iostream>
#include <cstdlib>
#include <cstring>
using namespace std;

char * strbrk( char *s1, char *s2);

int main()
{
    struct TestCase
    {
        char s1[64]; // using char buffers as strbrk() takes non-const char *s
        char s2[64];
        char expectedResult[64];
        int  expectedOffset;
    };

    static TestCase testCases[] = {
        {"abc", "a", "abc"  , 0},
        {"abc", "b", "bc"   , 1},
        {"abc", "c", "c"    , 2},        
        {"abc", "d", "NULL" , 0}
    };

    static const int count = sizeof(testCases)/sizeof(testCases[0]);
    
    int passes = 0;

    for(int i = 0; i < count; ++i)
    {
        TestCase& tc = testCases[i];

        cout << "TestCase #" << (i + 1) << "\n"
             <<  "s1 = " << tc.s1 << "\n"
             <<  "s2 = " << tc.s2 << "\n";

        char* p = strbrk(tc.s1, tc.s2);
        bool passed = false;
        if(p == NULL)
        {
            cout << "p = NULL\n";
            passed = (0 == strcmp(tc.expectedResult, "NULL"));
        }
        else
        {
            cout << "p = " << p << "\n"
                 << "offset = " << (p - tc.s1) << "\n";
            passed = (    (0 == strcmp(p, tc.expectedResult))
                       && ((p - tc.s1) == tc.expectedOffset)  );
        }
        if(passed)
        {
            cout << "- pass!\n";
            ++passes;
        }
        else
        {
            cout << "- fail!\n";
        }
        cout << "\n";
    }

    cout << "Passed " << passes << " out of " << count << " test cases.\n";

    return 0;
}

char * strbrk( char *s1, char *s2)
{
    char c;
    
    while ((*s1++ = c) != 0)
    {
      for( ; *s2 != 0 ; ++s2 )
            if (*s2 == c) // added * -- was s2 == c (which didn't compile)
               return s1; // lost (char *) cast as s1 already a char*
    }
    
    return (NULL);
}

[pacman169]

Hi,

Why not just use brute force? If you would know how to use it, I would be interested. How about using random() ? http://www.gnu.org/software/libc/manual/html_node/BSD-Random.html