c++ - Dynamically increase and decrease char arrays? -

i have send data udp. buffer field of type char. have encrypt/decrypt send. here's code encrypting/decrypting.

const unsigned buffer_size = 128; char data[buffer_size];  cout << "enter something." << endl; cin.getline(data, buffer_size); cout << data; char outchar[buffer_size];   for(int = 0; < strlen(data); i++) {     //outchar[i] = data[i];             outchar[i] = encr[(int)data[i]];             cout << outchar[i];  }  cout << "correct far" << endl;   char transchar[buffer_size]; for(int j = 0; j < strlen(outchar); j++) { transchar[j] = decr[(int)outchar[j]]; cout << transchar[j]; // prints out decrypted text , unused space! } 

the problem here using fixed size of char means there lot of unused space in buffer. in code provided, gets printed screen.

is there anyway dynamically increase , decrease buffer (char array) size not unused space?

edit: don't think clear: every letter has encrypted , decrypted! words not encrypted, letters make them are! advice given translate words array. need characters.

edit2: deleted.

edit3: russians, got love them. big vlad moscow!

the way dynamically allocate memory of required size. instead of doing manually can use standard class std::string pass stored data char array can use member functions c_str() or data()

for example

std::string data;  std::cout << "enter something." << std::endl; std::getline( std::cin, data ); std::cout << data; std::string outchar; outchar.reserve( data.size() );   for(int = 0; < data.size(); i++) {     //outchar[i] = data[i];             outchar.push_back( encr[ (int)data[i] ] );             std::cout << outchar.back();  } 

to use std::string need include header <string>