Compilare: main.cpp: In function 'int main()': main.cpp:51:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k = 1; k <= cuv.length(); ++k) ~~^~~~~~~~~~~~~~~ main.cpp:53:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int l = k; l <= cuv.length(); ++l) ~~^~~~~~~~~~~~~~~ main.cpp:64:32: warning: array subscript has type 'char' [-Wchar-subscripts] fr[matrix[i][j]].x = i; ^ main.cpp:65:32: warning: array subscript has type 'char' [-Wchar-subscripts] fr[matrix[i][j]].y = j; ^ main.cpp:74:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i <= cuv.length(); ++i) ~~^~~~~~~~~~~~~~~ main.cpp:76:34: warning: array subscript has type 'char' [-Wchar-subscripts] coada.push({fr[cuv[i - 1]].x, fr[cuv[i - 1]].y}); ^ main.cpp:76:52: warning: array subscript has type 'char' [-Wchar-subscripts] coada.push({fr[cuv[i - 1]].x, fr[cuv[i - 1]].y}); ^ main.cpp:80:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int le = 2; le <= cuv.length(); ++le) ~~~^~~~~~~~~~~~~~~ main.cpp:82:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 1; i + le - 1 <= cuv.length(); ++i) ~~~~~~~~~~~^~~~~~~~~~~~~~~