Compilare: user.cpp: In function ‘int main()’: user.cpp:96:112: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d %d %d %d %d %d %d", &N, &reff[1].v, &reff[2].v, &reff[1].l, &reff[1].c, &reff[2].l, &reff[2].c); ^ user.cpp:99:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", &val[i][j]); ^ user.cpp:120:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("vis.out", "w", stdout); ^