buggy_string.cpp

#include <iostream>
#include <cstdlib>


// prototype in function
char* myStrCpy(char* dest, const char* src);
bool matching(const char* str1, const char* str2);
static char* myStrCat(char* buffer, const char* readOnlyStr);
int positionIndex(const char* fullStr, const char* portionString);
static const char* myStrStr(const char* s1, const char* s2);
void myStrPosLen(const char* s1, int position, int length);
static char* myStrChr(const char* buffer, int firstOccurence);
size_t myStrLength(const char* buffer);
void insertString(const char* aa,const char* bb, int pos);

int main(void)
{
    char chunk[150] = "American International";
    const char* str = " University Bangladesh";

    std::cout << myStrCat(chunk, str) << std::endl;

    myStrPosLen("Hello This is Crucial Platform !", 13, 6);

    const char* fullString = "I am a student of AIUB";
    const char* porString = "of";

    int index = positionIndex(fullString, porString);
    if (index != -1) {
        std::cout << "the substring is found in the position of " << index << std::endl;
    }
    else {
        std::cout << "the substring is not there\n";
    }

    insertString("hello, This is a lab and very crucial one!"," data structure", 16);
}

static char* myStrCat(char* buffer, const char* readOnlyStr)
{
    char* crawler = buffer;

    // loop through the fixed given string
    while (*crawler != '\0') {
        crawler++;
    }
    // dereferencing the readOnlyStr back to first string
    while ((*crawler = *readOnlyStr) != '\0') {
        crawler++;
        readOnlyStr++;
    }

    return buffer;
}

int positionIndex(const char* fullStr, const char* portionString)
{
    const char* crawler = fullStr;
    int counter = 1;

    while (*crawler != '\0') {
        crawler++;
        counter++;
        if (*crawler == *portionString && matching(crawler, portionString)) {
            return counter;
            break;
        }
    }
    return -1;
}

static const char* myStrStr(const char* s1, const char* s2)
{
    if (*s2 == '\0')
        return ((char*)s1);

    for (; (s1 = myStrChr(s1, *s2)) != NULL; ++s1) {
        const char* sc1;
        const char* sc2;
        for (sc1 = s1, sc2 = s2;;) {
            if (*++sc2 == '\0')
                return ((char*)s1);

            else if (*++sc1 != *sc2)
                break;
        }
    }
    return NULL;
}

bool matching(const char* str1, const char* str2)
{
    if (myStrStr(str1, str2)) {
        return true;
    }
    else {
        return false;
    }
}

static char* myStrChr(const char* buffer, int firstOccurence)
{
    while (*buffer != (char)firstOccurence) {
        if (*buffer == '\0') {
            return NULL;
        }
        else {
            buffer++;
        }
    }

    return (char*)buffer;
}

char* myStrCpy(char* dest, const char* src)
{
    char* returnval = dest;

    while (*src != '\0') {
        *dest = *src;
        dest++;
        src++;
    }
    *dest = *src;
    return returnval;
}

void myStrPosLen(const char* s1, int position, int length)
{
    char dest[50] = "";
    myStrCpy(dest, s1);
    for (int i = position; i < length + position; i++) {
        std::cout << dest[i];
    }
    std::cout << std::endl;
}

void insertString(const char* aa, const char* bb, int pos)
{
    size_t srclen = myStrLength(bb);
    size_t dstlen = myStrLength(aa);
    // char* m = (char*)malloc(srclen + dstlen + 1);

    char dest[50] = "";
    char* temp = myStrCpy(dest, bb);

    std::cout << std::endl;
    for (int i = 0; i < 16; i++)
    {
        std::cout << aa[i];
    }
    std::cout << temp ;

    for( size_t  i = 0  ; i < srclen + dstlen; i++)
    {
        std::cout <<  aa[i + 16];
    }
}

size_t myStrLength(const char* buffer)
{
    static size_t length = 0;
    while (*buffer != '\0') {
        buffer++;
        length++;
    }
    return length;
}