代码有点长，没用switch，本来想通过在化简的，没想到提交全错，大佬幸苦了

#include<iostream>
#include<string>
using namespace std;
int lenhs(int );
int main()
{
	int sum1,sum2,x,i,n,f,sum,l;
	string s;
	cin>>n;
	cin.get();
	for(i=0;i<n;i++)
	{
		sum1=0;
		sum2=0;
		l=0;
		getline(cin,s);
		if(s[0]=='a')
		{
			f=1;
			x=2;
			while(s[x]!=' ')
			{
				l++;
				sum1=sum1*10+(s[x]-'0');
				x++;
			}
			x++;
			while(x<s.length())
			{
				l++;
				sum2=sum2*10+(s[x]-'0');
				x++;
			}
			sum=sum1+sum2;
			l=l+lenhs(sum)+2;
			cout<<sum1<<"+"<<sum2<<"="<<sum<<endl;
			cout<<l<<endl; 
		}
		else if(s[0]=='b')
		{
			f=2;
			x=2;
			while(s[x]!=' ')
			{
				l++;
				sum1=sum1*10+(s[x]-'0');
				x++;
			}
			x++;
			while(x<s.length())
			{
				l++;
				sum2=sum2*10+(s[x]-'0');
				x++;
			}
			sum=sum1-sum2;
			l=l+lenhs(sum)+2;
			cout<<sum1<<"-"<<sum2<<"="<<sum<<endl;
			cout<<l<<endl; 
		}
		else if(s[0]=='c')
		{
			f=3;
			x=2;
			while(s[x]!=' ')
			{
				l++;
				sum1=sum1*10+(s[x]-'0');
				x++;
			}
			x++;
			while(x<s.length())
			{
				l++;
				sum2=sum2*10+(s[x]-'0');
				x++;
			}
			sum=sum1*sum2;
			l=l+lenhs(sum)+2;
			cout<<sum1<<"*"<<sum2<<"="<<sum<<endl;
			cout<<l<<endl; 
		}
		else if(s[0]<'a')
		{
			if(f==1)
			{
				x=0;
				while(s[x]!=' ')
				{
					l++;
					sum1=sum1*10+(s[x]-'0');
					x++;
				}
				x++;
				while(x<s.length())
				{
					l++;
					sum2=sum2*10+(s[x]-'0');
					x++;
				}
				sum=sum1+sum2;
				l=l+lenhs(sum)+2;
				cout<<sum1<<"+"<<sum2<<"="<<sum<<endl;
				cout<<l<<endl; 
			}
			if(f==2)
			{
				x=0;
				while(s[x]!=' ')
				{
					l++;
					sum1=sum1*10+(s[x]-'0');
					x++;
				}
				x++;
				while(x<s.length())
				{
					l++;
					sum2=sum2*10+(s[x]-'0');
					x++;
				}
				sum=sum1-sum2;
				l=l+lenhs(sum)+2;
				cout<<sum1<<"-"<<sum2<<"="<<sum<<endl;
				cout<<l<<endl; 
			}
			if(f==3)
			{
				x=0;
				while(s[x]!=' ')
				{
					l++;
					sum1=sum1*10+(s[x]-'0');
					x++;
				}
				x++;
				while(x<s.length())
				{
					l++;
					sum2=sum2*10+(s[x]-'0');
					x++;
				}
				sum=sum1*sum2;
				l=l+lenhs(sum)+2;
				cout<<sum1<<"*"<<sum2<<"="<<sum<<endl;
				cout<<l<<endl; 
			}
		}
	}
	return 0;
}
int lenhs(int n)
{
	int l=0;
	if(n<0)	l++;
	while(n!=0)
	{
		n=n/10;
		l++;
	}
	return l;
}