use + for string concatenation in c++

Question

Hello everyone,
   Use the + connection string error occurs, the code is as follows:

It is a reference Vulpes sir great article:http://www.c-sharpcorner.com/UploadFile/b942f9/converting-numbers-to-words-in-C-Sharp/



#include<iostream>
#include <stdlib.h>
#include <string>
using namespace std;


string NumberToWords(int number,bool isUK)
{
if(number==0) return "Zero";
string and=isUK?"and ": ""; // deals with UK or US numbering
if(number==-2147483648) 
return (string)"Minus Two Billion One Hundred "+and+"Forty Seven Million Four Hundred "+and+"Eighty Three Thousand "+
"Six Hundred "+and+"Forty Eight";
    int *num=new int[4];
    int first=0,u,h,t;
string sb;

if(number<0)
{
sb+="Minus";
number=-number;
}
string words0[]={"","One ","Two ", "Three ", "Four ", "Five ", "Six ", "Seven ", "Eight ", "Nine "};
string words1[]={"Ten ", "Eleven ", "Twelve ", "Thirteen ", "Fourteen ", "Fifteen ", "Sixteen ", "Seventeen ", "Eighteen ", "Nineteen "};
string words2[]={"Twenty ", "Thirty ", "Forty ", "Fifty ", "Sixty ", "Seventy ", "Eighty ", "Ninety "};
    string words3[]={"Thousand ", "Million ", "Billion " };
num[0]=number % 1000;           // units
num[1]=number / 1000;
num[2]=number / 1000000;

num[1]=num[1] - 1000 * num[2];  // thousands
num[3]=number / 1000000000;     // billions
    num[2]=num[2]-1000 * num[3];  // millions


for (int i=3;i>0;i--)
{
if(num[i]!=0)
{
first=i;  // The maximum number of obtained 
break;
}
}
for (int j=first;j>=0;j--)
{

if(num[j]==0) continue;
u=num[j]%10;  // ones
t=num[j]/10;
h=num[j]/100; // hundreds
t=t-10*h;     // tens
if(h>0) sb+=words0[h]+"Hundred";
if(u>0||t>0)
{
if(h>0||i<first) sb+=and;
if(t==0) sb+=words0[u];
else if(t==1) sb+=words1[u];
else sb+=words2[t-2]+words0[u];
}
if(i!=0) sb+=words3[i-1];
}
return (string)sb;
}



int main(void)
{
    string input;
int number;
bool isValid;
bool isUK=false;
cout<<"\nEnter '0' to quit the program at any time\n";
    while (true)
    {
cout<<"\nUse UK numbering y/n:";
cin>>input;
if(!(toupper(input)=="Y"||toupper(input)=="N"))
cout<<"\nMust be 'y' or 'n', please try again\n";
else
{
           if(toupper(input)=="Y") isUK=true;
  cout<<'\n';
  break;
}
    }
do 
{
cout<<"Enter integer:";
cin>>input;
isValid=(atoi(input))>0?true:false;
if(!isValid) cout<<"\n  Not an integer, please try again\n";
else cout<<"\n"<<NumberToWords(number,isUK)<<endl;
} while (!(isValid&&number==0));
cout<<"\nProgram ended"<<endl;
return 0;
}

thanks.