Compilare: main.cpp: In function 'int main()': main.cpp:42:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 1; i<= n; i++) ~^~~~ main.cpp:43:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 1; j<= m; j++) ~^~~~ main.cpp:51:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j<n; j++) ~^~ main.cpp:54:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (counter == r) ~~~~~~~~^~~~ main.cpp:59:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k = 0; k<m; k++) ~^~ main.cpp:62:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (counter==c) ~~~~~~~^~~