#include <stdio.h>
#include <string.h>

#define ITEMS_OF(a) (sizeof(a)/sizeof(a[0]))

void CalcLetterMap(const char *op, char *letters)
{
    const char *p = op;

    while (*p)
    {
        letters[*p] = 1;
        ++p;
    }
}

int SameLetters(const char *op1, const char * op2)
{
    char op1Letters[256], op2Letters[256];

    memset(op1Letters, 0, sizeof(op1Letters) / sizeof(op1Letters[0]));
    memset(op2Letters, 0, sizeof(op2Letters) / sizeof(op2Letters[0]));

    CalcLetterMap(op1, op1Letters);
    CalcLetterMap(op2, op2Letters);

    int ret = memcmp(op1Letters, op2Letters, sizeof(op1Letters));

    return ret == 0;
}

struct TEST_ENTRY
{
    const char *op1;
    const char *op2;
    int ExpectedResult;
}
TestArray[] =
{
    {"aaaaa", "a", 1},
    {"aaaaa", "b", 0},
    {"abababc", "cba", 1},
    {"abcdef", "abcdef", 1},
    {"abcdef", "abcde", 0},
    {"aaabbbccc888", "88888aaaaa88888aaaaa88888aaa888888aaaaaaabbbbbbbcccbbccbbc", 1},
    {"a", "a", 1},
    {"ab", "ba", 1},
    {"a", "b", 0},
    {"444444444444", "555555555555555555", 0},
    {"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ", "QWERTYUIOPLKJHGFDSAZXCVBNM0987654321mnbvcxzasdfghjklpoiuytrewq", 1},
    {"xa ax", "Xa ax", 0},
};

int main(void)
{

    for (unsigned int testIndex = 0; testIndex < ITEMS_OF(TestArray); ++testIndex)
    {
        struct TEST_ENTRY * pTest = &TestArray[testIndex];

        int result = SameLetters(pTest->op1, pTest->op2);
        printf("%s: SameLetters(%s,%s)\n", (result != pTest->ExpectedResult) ? "FAIL" : "PASS", pTest->op1, pTest->op2);

        result = SameLetters(pTest->op2, pTest->op1);
        printf("%s: SameLetters(%s,%s)\n", (result != pTest->ExpectedResult) ? "FAIL" : "PASS", pTest->op2, pTest->op1);

    }

    return 0;
}