Compilare: main.cpp: In function 'int main()': main.cpp:37:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("alpin.in","r",stdin); ^ main.cpp:38:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:41:35: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] int x; scanf("%d", &x); a[++k]={i,j,x}; b[i][j]=x; ^