Compilare: main.cpp: In function 'int main()': main.cpp:18:27: warning: left operand of comma operator has no effect [-Wunused-value] for(int i=k,j=1; i<=n,j<=n; i++,j++) ~^~~ main.cpp:29:27: warning: left operand of comma operator has no effect [-Wunused-value] for(int i=1,j=k; i<=n,j<=n; i++,j++) ~^~~ main.cpp:40:27: warning: left operand of comma operator has no effect [-Wunused-value] for(int i=n,j=k; i>=1,j<=n; i--,j++) ~^~~ main.cpp:50:27: warning: left operand of comma operator has no effect [-Wunused-value] for(int i=k,j=1; i>=1,j<=n; i--,j++) ~^~~