C++

Q: Some important String functions?
  1)  char *strstr(char *string2, char string*1);
        The strstr function locates the first occurrence of the string string1 in the string string2 and returns a pointer to the beginning of the first occurrence.
2) char *strtok(char *s, const char *delim) ;
A sequence of calls to this function split str into tokens, which are sequences of contiguous characters separated by any of the characters that are part of delimiters.

3) void perror(const char *s);

The perror() function shall map the error number accessed through the symbol errno to a language-dependent error message, which shall be written to the standard error stream as follows:

Q: General form of Templates in C++?

The general form of a template function definition is shown here:

template <class type>

ret-type func-name(parameter list)

{

   // body of function

}

General form class template

template <class type>
class class-name{
//class members and funtions
};
Example of stack<>

#include <iostream>

#include <vector>

#include <cstdlib>

#include <string>

using namespace std;

template <class T>

class Stack {

  private:

    vector<T> elems;     // elements

  public:

    void push(T const&);  // push element

    void pop();               // pop element

    T top() const;            // return top element

    bool empty() const{       // return true if empty.

        return elems.empty();

    }

};

template <class T>

void Stack<T>::push (T const& elem)

{

    // append copy of passed element

    elems.push_back(elem);   

}

template <class T>

void Stack<T>::pop ()

{

    if (elems.empty()) {

        throw out_of_range("Stack<>::pop(): empty stack");

    }

         // remove last element

    elems.pop_back();        

}

template <class T>

T Stack<T>::top () const

{

    if (elems.empty()) {

        throw out_of_range("Stack<>::top(): empty stack");

    }

         // return copy of last element

    return elems.back();     

}

int main()

{

    try {

        Stack<int>         intStack;  // stack of ints

        Stack<string> stringStack;    // stack of strings

        // manipulate int stack

        intStack.push(7);

        cout << intStack.top() <<endl;

        // manipulate string stack

        stringStack.push("hello");

        cout << stringStack.top() << std::endl;

        stringStack.pop();

        stringStack.pop();

    }

    catch (exception const& ex) {

        cerr << "Exception: " << ex.what() <<endl;

        return -1;

    }

}