Compilare: user.cpp: In function ‘void dfs(int, int)’: user.cpp:65:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[nod].size();++i) if(v[nod][i]!=ant&&v[nod][i]) dfs(v[nod][i],nod); ^ user.cpp: In function ‘int sterge(int, int)’: user.cpp:80:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[nod1].size();++i) if(v[nod1][i]!=ant1&&v[nod1][i]) {++t1;qa.push({v[nod1][i],nod1});} ^ user.cpp:81:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[nod2].size();++i) if(v[nod2][i]!=ant2&&v[nod2][i]) {++t2;qb.push({v[nod2][i],nod2});} ^ user.cpp:89:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[nod1].size();++i) if(v[nod1][i]!=ant1) {++t1;qa.push({v[nod1][i],nod1});} ^ user.cpp:97:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<v[nod2].size();++i) if(v[nod2][i]!=ant2) {++t2;qb.push({v[nod2][i],nod2});} ^ user.cpp:104:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:124:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[a].size();++j) if(v[a][j]==b) {v[a][j]=0;break;} ^ user.cpp:125:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<v[b].size();++j) if(v[b][j]==a) {v[b][j]=0;break;} ^ user.cpp: In member function ‘char InParser::read_ch()’: user.cpp:18:38: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buff, 1, 4096, fin); ^