compilation error

i am writing a program which will find a string from an array of strings.

PHP Code:


#include<iostream>
 #include<cstdlib>
 #include<string>
 #include<cmath>
 #include<vector>
 using namespace std;

 typedef  std::<vector std::string> str;

 str s("abcd","efgh","ijkl","mnop","123"); //  string initialized

 int main()

 {

 string s1="ijkl"; // target string

 std::vector<std::string> iterator p ;

for(iterator p = s.begin(); p!=s.end();p++)
{

 if( s1==s[p]) cout<<"string has been found"<<endl;  // string has been found

}

int n = atoi("123");  // is it possible in C++ ?
cout<<n<<endl;


} 


my errors >

error C2589: '<' : illegal token on right side of '::'
error C2589: '<' : illegal token on right side of '::'
warning C4091: 'typedef ' : ignored on left of 'int' when no variable is declared
error C2143: syntax error : missing ';' before '::'
error C2143: syntax error : missing ';' before '::'
error C2955: 'vector' : use of class template requires template argument list
c:\program files\microsoft visual studio\vc98\include\vector(244) : see declaration of 'vector'
error C2146: syntax error : missing ';' before identifier 's'
error C2501: 'str' : missing storage-class or type specifiers
fatal error C1004: unexpected end of file found
Error executing cl.exe.


why these errors ? how can i fix those errors ?
thanks

Code:

#include<iostream> 
#include<cstdlib> 
#include<string> 
#include<cmath> 
#include<vector> 
using namespace std; 

typedef  std::vector <std::string> str; 

int main() 
{ 
  str s;
  s.push_back("abcd");
  s.push_back("efgh");
  s.push_back("ijkl");
  s.push_back("mnop");
  s.push_back("123");
  string s1="ijkl"; // Also unnecessary comment, use a better name
  std::vector<std::string>::iterator p; 
  for(p = s.begin(); p!=s.end();p++) 
  { 

    if( s1==*p) cout<<"string has been found"<<endl;  // Unnecessary comment

  } 
  int n = atoi("123");  // Yes, it is possible. :-)
  cout<<n<<endl; 
}

The more obvious errors are:

>typedef std::<vector std::string> str;
Misplaced opening angle bracket. It should be:

Code:

typedef  std::vector <std::string> str;

>str s("abcd","efgh","ijkl","mnop","123"); // string initialized
Sadly, you cannot initialize a vector like this.

>std::vector<std::string> iterator p ;
iterator is a data type of the vector class, use the scope resolution operator to access it:

Code:

std::vector<std::string>::iterator p;

>for(iterator p = s.begin(); p!=s.end();p++)
p already exists, you're trying to declare it again with an unknown type. This should be:

Code:

for(p = s.begin(); p!=s.end();p++)

>if( s1==s[p])
An iterator is like a pointer, not like an index. s[p] is an undefined operation. Instead, dereference the iterator like a pointer:

Code:

if( s1==*p)

>int n = atoi("123"); // is it possible in C++ ?
Yes it is possible, but calling atoi on a string literal directly serves no purpose. It would be easier and faster to simply do this:

Code:

int n = 123;

thanks prelude . i understood the errors. i have one more question.

Code:

#include<iostream>
 #include<cstdlib>
 #include<string>
 #include<cmath>
 #include<vector>
 using namespace std;



 int main()

 {



string  s1 = "123";
int n = atoi(s1);        // code-1  .....this code is giving compile error 

cout<<n<<endl; 







int n = atoi("123");     // code-2....... this code is ok
cout<<n<<endl;



}

i want the code-1 ready... bcoz i want to store string in a variable and then want to use atoi() to get integers .


how can i remove error from code-1 ?

code-1 is giving error >

cannot convert `std::string' to `const char*' for argument `1' to `
int atoi(const char*)'
(g++ compiler)


what this error demands ?
is it possible to remove error from the code-1 ?

thanks

>int n = atoi(s1);
s1 is a C++ string, but atoi takes a C-style string. To get a const char * from a C++ string, use the c_str member function:

Code:

int n = atoi(s1.c_str());