#include<cstdio>#include<iostream>#include<string>usingnamespace std;int n;
string s;boolcheck(string s){if((s[0]=='+'||s[0]=='-')&& s.size()==1)returnfalse;if(s[0]=='+'||s[0]=='-') s=s.substr(1);int k=0,index=0;for(int i=0;i<s.size();i++){if(s[i]=='.') k++,index=i+1;elseif(s[i]<'0'||s[i]>'9')returnfalse;}if(k>=2)returnfalse;if(k==0)returntrue;if((s.size()-index)>2)returnfalse;returntrue;}intmain(void){cin>>n;double sum=0;int cnt=0;bool flag=false;for(int i=0;i<n;i++){cin>>s;if(check(s)){double temp=stod(s);if(temp>=-1000.0&&temp<=1000.0) sum+=temp,cnt++,flag=true;elseprintf("ERROR: %s is not a legal number\n",s.c_str());}elseprintf("ERROR: %s is not a legal number\n",s.c_str());}if(flag&&cnt!=1)printf("The average of %d numbers is %.2lf\n",cnt,sum/cnt);elseif(flag)printf("The average of %d number is %.2lf\n",1,sum);elseprintf("The average of 0 numbers is Undefined");return0;}#include<bits/stdc++.h>usingnamespace std;int cnt,t;double sum;boolcheck(string s){string temp=s;int k=0;if(temp[0]=='-'||temp[0]=='+') temp=temp.substr(1);for(int i=0;i<temp.size();i++){if(temp[i]=='.') k++;elseif(temp[i]<'0'||temp[i]>'9')returnfalse;}if(k>1)returnfalse;if(k){int l=temp.find('.');int len=temp.size()-l-1;if(len>2)returnfalse;}double a=stod(s);if(a>=-1000.0&&a<=1000.0)returntrue;elsereturnfalse;}intmain(void){cin>>t;while(t--){string s; cin>>s;if(check(s)) cnt++,sum+=stod(s);elseprintf("ERROR: %s is not a legal number\n",s.c_str());}if(cnt>1)printf("The average of %d numbers is %.2lf",cnt,sum/cnt);elseif(cnt==1)printf("The average of %d number is %.2lf",cnt,sum/cnt);elseprintf("The average of 0 numbers is Undefined");return0;}