c++ - Constructor gets ignored -
my constructor gets ignored somehow. here code:
my class:
class field { private: char playfield[5][5]; public: char o = 'o'; field() { char playfield[5][5] = { { o, o, o, o, o }, { o, o, o, o, o }, { o, o, o, o, o }, { o, o, o, o, o }, { o, o, o, o, o } }; } void settile(int x_val, int y_val) { playfield[x_val][y_val] = 'x'; } char gettile(int x_val, int y_val) { return playfield[x_val][y_val]; } /*field::~field();*/ }; the constructor field() should initalize 4 wins field 'o's , if want add tile x mark tile is. if do
int main() { char x; field fourwins; //fourwins.settile(3, 2); x = fourwins.gettile(3, 2); std::cout << x << std::endl; return 0; } the constructor ignored , weired sign @ i'm looking. position finding works, becouse if first set , x (3,2) print me x.
any ideas?
the initialization syntax char[][] used allowed, @ construction - not assignment (and example constructed new variable rather assigned member variable). @ least c++14 can this:
class field { private: char o = 'o'; char playfield[5][5]; public: field() : playfield{{ o, o, o, o, o }, { o, o, o, o, o }, { o, o, o, o, o }, { o, o, o, o, o }, { o, o, o, o, o }} {} }; consider using std::vector of std::vector, or std::array of std::array instead. down side of using std::array compared char[5][5] sizes (5x5 in case) must known @ compile time (just in example)
#include <iostream> #include <array> #include <vector> using namespace std; int main() { char o='a'; // c++11 or later: std::array<std::array<char,5>, 5> playfield2{{{o,o,o,o,o},{o,o,o,o,o}, {o,o,o,o,o},{o,o,o,o,o},{o,o,o,o,o}}}; // or: (c++11 or later) std::array<std::array<char,5>, 5> playfield; for(auto& row : playfield){ for(auto& place : row){ place=o; } } cout << playfield[2][3] << std::endl; // or: (c++98 or later) std::vector<std::vector<char>> playfieldvec(5,std::vector<char>(5,o)); cout << playfieldvec[2][3] << std::endl; } the syntax used array initialization fine, make sure don't assign new variable if mean initiate existing one.
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