Compilare: user.cpp: In function ‘int main()’: user.cpp:26:8: warning: unused variable ‘fout’ [-Wunused-variable] FILE*fout=fopen("trapez.out", "w"); ^ user.cpp:28:24: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d", &n); ^ user.cpp:30:42: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &lin[i], &col[i]); ^