Compilare: user.cpp: In function ‘int main()’: user.cpp:7:21: warning: unused variable ‘a’ [-Wunused-variable] int n, m, i, j, a, dif=0, d, lin, col, st=0; ^ user.cpp:5:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "spirala.in", "r", stdin ); ^ user.cpp:6:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "spirala.out", "w", stdout ); ^ user.cpp:8:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d%d", &n, &m ); ^ user.cpp:15:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d", &mat[i][j] ); ^