Compilare: main.cpp: In function 'int main()': main.cpp:33:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<v2[w[i].secon].size();j++){ ~^~~~~~~~~~~~~~~~~~~~~~ main.cpp:21:34: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d%d",&taste,&n); ^ main.cpp:23:34: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d%d",&x,&y); ^