Compilare: user.cpp: In function ‘int main()’: user.cpp:81:10: warning: unused variable ‘ch’ [-Wunused-variable] char ch; ^ user.cpp:82:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d\n",&n); ^ user.cpp:84:34: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(mat[i]+1,lgmax,fin); ^