Please help with String

[tinhnho]

Write the following member function:
// strcmp is negative if s < s1
// is 0 if s == s1
// and positive if s > s1
// where s is the emplicite argument

int my_string::strcmp(const my_string& s1);


// strrev reverses the my_string
void my_string::strrev();


//print oeverloaded to print the frist n characters
void my_string:: print(int n);


here is what i got so far:

code:

#include <iostream> #include <cstdlib> #include <string> using namespace std; class my_string { public:    my_string();    my_string(const my_string& str);    my_string(const char* p);    ~my_string();    int strcmp(const my_string& s1);    void strrev();    void print(int n);    int const getLen();    const char* getS(); private:       char* s;       int len; }; my_string::my_string(): len(0),s (0){} my_string::my_string(const char* p) {    len = strlen (p);    s = new char[len +1];    assert(s !=0);    strcpy(s, p); } my_string::my_string(const my_string& str):len(str.len) {    s = new char[len+1];    assert(s !=0);    strcpy(s, str.s); } // Destructor my_string::~my_string() {    delete [] s; } int my_string::strcmp(const my_string& s1) {    int i;    for(i=0; s1.s[i] && s[i] && s1.s[i] == s[i]; ++i)    {       return s1.s[i]-s[i];    } } void my_string::strrev() {     my_string strrev;     char* temp = new char[len + 1];     int i= 0;     int j= 0;     while (s[i])     {        temp[j++] = s[i--];     }     temp[j] ='\0';     strcpy(s,temp);     delete[] temp; } void my_string::print(int n) {    return ; } int const my_string::getLen() {    return len; } const char* my_string::getS() {    return s; } int main () {    my_string myStr ("same");    if (myStr.strcmp ("same") < 0)       cout << myStr.getS() << " < " << "same" << endl;    else if (myStr.strcmp ("same") == 0)       cout << myStr.getS() << " = " << "same" << endl;    else       cout << myStr.getS() << " > " << "same" << endl;    cout << "Reverse string " << myStr.getS() << " to ";    myStr.strrev();    myStr.print();    system("pause"); }

when i compile it ,the compiler telling me the error: " No matching function for call to my_string::print()" and "Candidates are : void my_string::print()".Please tell me where did i go wrong,thanks alot

Note:

code:

Use the following string to test your function strcmp:       1st string                                2nd string        gladiator                                 gladiolus        xyz                                        abcd        same                                      same

Can not use predefined strrev function.

[Tony]

eh... looks complicated... isn't there already string.compare() function? or is that java?

anyways, its something like

code:

int compare(string word1, string word2) { for(int i=0; i<word1.length;i++) { if word1.substr(i,1) < word2.substr(i,1) return -1 if word1.substr(i,1) > word2.substr(i,1) return 1 } return 0 }

I think basically you just keep on comparing one character at a time (using substrings) untill you find pair that is different... or run out of characters - then strings are the same.

[wtd]

It's C++, and the problem is that you've defined the print function to take one argument of type int, yet when you call it, you call it without arguments.

[tinhnho]

wtd wrote:

It's C++, and the problem is that you've defined the print function to take one argument of type int, yet when you call it, you call it without arguments.

should i go for this:

code:

void my_string::print(int n) {    return my_string(s,n); }

[Tony]

tinhnho - a void function cannot have a return statement

[tinhnho]

my bad,it should not have statemen in there

[tinhnho]

here is what i have done.I compiled it and it said something about run time error , there are no message error.I'm using Dev C++.Thanks

code:

#include <iostream> #include <cstdlib> #include <string> using std::cout; class my_string { public:    my_string();    my_string(const my_string& str);    my_string(const char* p);    ~my_string();    int strcmp(const my_string& s1);    void strrev();    void print(int n=0);    int const getLen();    const char* getS(); private:    char* s;    int len; }; my_string::my_string(): len(0),s (0){} my_string::my_string(const char* p) {    len = strlen (p);    s = new char[len +1];    assert(s !=0);    strcpy(s, p); } my_string::my_string(const my_string& str):len(str.len) {    s = new char[len+1];    assert(s !=0);    strcpy(s, str.s); } // Destructor my_string::~my_string() {    delete [] s; } //strcmp int my_string::strcmp(const my_string& s1) {    int i;    while(s1.s[i] && s[i] && s1.s[i] == s[i])    {        i++;    }    return s1.s[i]-s[i]; } //strrev void my_string::strrev() {    char* temp = new char[len + 1];    int i = len -1;    int j= 0;    while (s[i])    {       temp[j++] = s[i--];    }    temp[j] ='\0';    strcpy(s,temp);    delete[] temp; } void my_string::print(int n) {    if (n > len || n == 0) n = len;    for (int i = 0; i < n; ++i)    cout << s[i];    cout << endl; } int const my_string::getLen() {    return len; } const char* my_string::getS() {    return s; } int main () {    my_string myStr("gladiator");    if (myStr.strcmp ("gladiolus") < 0)       cout << myStr.getS() << " < " << "gladiolus" << endl;    else if (myStr.strcmp ("gladiolus") == 0)       cout << myStr.getS() << " = " << "gladiolus" << endl;    else       cout << myStr.getS() << " > " << "gladiolus" << endl;    cout << "Reverse string " << myStr.getS() << " to ";    myStr.strrev();    myStr.print();    system("pause"); }

[wtd]

Hopefully the following will prove educational. I cleaned it up quite a bit.

code:

#include <iostream> #include <cstdlib> #include <string> class my_string {         private:                 char * s;                 int len;         public:                 my_string();                 my_string(const my_string& str);                 my_string(const char * p);                 ~my_string();                 int compare(const my_string& s1) const;                 void reverse();                 int length() const;                 const char * c_string() const;                 friend std::ostream& operator<<(std::ostream& out, const my_string& str); }; //********************************************* int main () {         using namespace std;         my_string my_str("Same");         switch (my_str.compare("SAme"))         {                 case -1:                         cout << my_str << " < " << "SAme" << endl;                         break;                 case 0:                         cout << my_str << " = " << "SAme" << endl;                         break;                 case 1:                         cout << my_str << " > " << "SAme" << endl;                         break;                 default:                         cout << "Uh... that shouldn't have happened..." << endl;         }         cout << "Reverse string " << my_str << " to ";         my_str.reverse();         cout << my_str << endl;         system("pause"); } //********************************************* my_string::my_string() : len(0) , s(0) { } my_string::my_string(const char * p) : len(strlen(p)) {         s = new char[len + 1];         assert(s != 0);         strncpy(s, p, strlen(p)); } my_string::my_string(const my_string& str) : len(str.length()) {         s = new char[len + 1];         assert(s != 0);         strncpy(s, str.c_string(), str.length()); } // Destructor my_string::~my_string() {         delete [] s; } int my_string::compare(const my_string& s1) const {         return strcmp(c_string(), s1.c_string()); } void my_string::reverse() {         my_string new_string;         char * temp = new char[length()];     for (int i = 0; i < length(); i++)                 temp[length() - i - 1] = s[i];         strncpy(s, temp, length()); } int my_string::length() const {         return len; } const char * my_string::c_string() const {         return s; } std::ostream& operator<<(std::ostream& out, const my_string& str) {         return out << str.c_string(); }