PTA乙级 (*1054 求平均值 (20分))
1054 求平均值 (20分)
https://pintia.cn/problem-sets/994805260223102976/problems/994805272659214336
#include <cstdio> #include <cstring> #include <string> #include <iostream> #include <cmath> #include <algorithm> #include <iomanip> using namespace std; bool check(string &str) { bool flag=false; int i=0,a=0,b=0; if(str[i]=='-') i++; for(;i<str.size();i++) { if((!isdigit(str[i]))&&(str[i]!='.')) return false; if(str[i]=='.') { a++; flag=true; continue; } if(flag) b++; } if(a>1||b>2||stod(str)>1000||stod(str)< -1000) return false; else return true; } int main() { int n,count=0; string str; double sum=0; cin>>n; for(int i=0;i<n;i++) { cin>>str; if(!check(str)) cout<<"ERROR: "<<str<<" is not a legal number\n"; else if(check(str)){ count++; sum+=stod(str); } } if(count==0) cout<<"The average of 0 numbers is Undefined\n"; else if(count==1) cout<<"The average of 1 number is "<<fixed<<setprecision(2)<<sum<<endl; else printf("The average of %d numbers is %.2f\n",count,sum/count); return 0; }
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