PAT乙级1054 求平均值 (20 分)

Posted 2021-08-08 辉小歌

题目地址

测试点 2：k==1 number没有s
测试点 3：12. 这种是合法的

#include<cstdio>
#include<iostream>
#include<string>
#include<algorithm> 
using namespace std;
bool check(string s)
{
	
	if( (s[0]<'0'||s[0]>'9') &&s[0]!='+'&&s[0]!='-') return false;
	if((s[0]=='+'||s[0]=='-')&&s.size()==1) return false;
	if(s[0]=='+'||s[0]=='-') s=s.substr(1);
	int k=0;
	for(int i=0;i<s.size();i++)
	{
		if(s[i]=='.') 
		{
			k++;
		}
		else if(s[i]<'0'||s[i]>'9') return false;
	}
	if(k>=2) return false;
	return true;
}
int n,k;
double sum;
string s;
int main(void)
{
	cin>>n;
	for(int i=0;i<n;i++)
	{
		cin>>s;
		bool flag=true;
		if(check(s))
		{
			double temp=stod(s);
			if(s.find('.')!=-1)
			{
				int t=s.find('.');
				if( (s.size()-1-t)<=2&&temp>=-1000&&temp<=1000)
				{
					sum+=temp;
					k++;
					flag=false;
				}
			}
			else
			{
				if(temp>=-1000&&temp<=1000)
				{
					sum+=temp;
					k++;
					flag=false;
				}
			}
			if(flag)
			{
				printf("ERROR: %s is not a legal number\\n",s.c_str());
			}
		}
		else printf("ERROR: %s is not a legal number\\n",s.c_str());
	}
	if(k>1) printf("The average of %d numbers is %.2lf\\n",k,sum/k);
	else if(k==1) printf("The average of 1 number is %.2lf\\n",sum);
	else printf("The average of 0 numbers is Undefined\\n"); 
	return 0;
}

#include<cstdio>
#include<iostream>
#include<string>
using namespace std;
int n;
string s;
bool check(string s)
{
	if( (s[0]=='+'||s[0]=='-') && s.size()==1) return false;
	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;
		else if(s[i]<'0'||s[i]>'9') return false;
	}
	if(k>=2) return false;
	if(k==0) return true;
	if( (s.size()-index)>2 ) return false;
	return true;
}
int main(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;
            else printf("ERROR: %s is not a legal number\\n",s.c_str());
		}
		else printf("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);
	else if(flag) printf("The average of %d number is %.2lf\\n",1,sum);
	else printf("The average of 0 numbers is Undefined");
	return 0;
}