Compilare: user.cpp: In function ‘void bf(int, int, int, int)’: user.cpp:48:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<a[x1].size();i++) ^ user.cpp:50:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<a[x2].size();j++) ^ user.cpp: In function ‘void solve()’: user.cpp:64:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<a[x].size();i++) ^ user.cpp:65:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j=0;j<a[x].size();j++) ^ user.cpp:70:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i=0;i<a[x].size();i++) ^ user.cpp: In function ‘void read()’: user.cpp:27:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&n); ^ user.cpp:30:31: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&x,&y); ^ user.cpp:34:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%c",&c); ^ user.cpp:35:12: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fcat(c); ^ user.cpp:38:29: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%c",&v[i]); ^ user.cpp:39:26: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%c",&c); ^