my answers are matched with test cases but can't passed the test cases

include

include

using namespace std;

int main() { int T; cin >> T; cout << setiosflags(ios::uppercase); cout << setw(0xf) << internal; while(T--) { double A; cin >> A; double B; cin >> B; double C; cin >> C; int integer=A; int devident=integer;//100 int devisor=16; string hexa=""; string tempString=""; int length=0; int rem;
while(devident) {
int temp=devident/devisor; rem=devident%devisor; devident=temp; if(rem<10){ tempString=48+rem; hexa=tempString+hexa; } else{ tempString=87+rem; hexa=tempString+hexa;

        }



    }
    cout<<setw(0);
    cout<<"0x";
    cout << hexa <<endl;
    int in=B;
    double decimal=B-in;
    int third=(decimal*1000);
    third=third%10;
    int temp=decimal*100;
    if(temp==0)
    {   

        decimal=0.01;
    }
    if(third>=5)
    {
        temp++;
    }
    else if(temp<10)
    {  
        decimal=temp*0.001;
    }
    else{
        decimal=temp*0.01;
    }
    B=decimal+in;
    string prefix="";
    while(in>0)
    {
        in=in/10;
        length++;
        prefix+="_";
    }
        for(int i=0;i<11-length*2;i++)
        {
            prefix+="_";
        }



    if(B>0)
    {
        prefix+="+";
        cout<<prefix<<fixed<< setprecision(2)<<B<<endl;

    }
    else{
        prefix+="-"; 
          cout <<prefix<<fixed << setprecision(2)<<B<<endl;
    }
    ;


    cout <<scientific<<setprecision(9)<<C<<endl;  
    /* Enter your code here */
}``

my answers are matched with test cases but can't passed the test cases

include

include

using namespace std;

int main() { int T; cin >> T; cout << setiosflags(ios::uppercase); cout << setw(0xf) << internal; while(T--) { double A; cin >> A; double B; cin >> B; double C; cin >> C; int integer=A; int devident=integer;//100 int devisor=16; string hexa=""; string tempString=""; int length=0; int rem;
while(devident) {
int temp=devident/devisor; rem=devident%devisor; devident=temp; if(rem<10){ tempString=48+rem; hexa=tempString+hexa; } else{ tempString=87+rem; hexa=tempString+hexa;

        }



    }
    cout<<setw(0);
    cout<<"0x";
    cout << hexa <<endl;
    int in=B;
    double decimal=B-in;
    int third=(decimal*1000);
    third=third%10;
    int temp=decimal*100;
    if(temp==0)
    {   

        decimal=0.01;
    }
    if(third>=5)
    {
        temp++;
    }
    else if(temp<10)
    {  
        decimal=temp*0.001;
    }
    else{
        decimal=temp*0.01;
    }
    B=decimal+in;
    string prefix="";
    while(in>0)
    {
        in=in/10;
        length++;
        prefix+="_";
    }
        for(int i=0;i<11-length*2;i++)
        {
            prefix+="_";
        }



    if(B>0)
    {
        prefix+="+";
        cout<<prefix<<fixed<< setprecision(2)<<B<<endl;

    }
    else{
        prefix+="-"; 
          cout <<prefix<<fixed << setprecision(2)<<B<<endl;
    }
    ;


    cout <<scientific<<setprecision(9)<<C<<endl;  
    /* Enter your code here */
}

WHAT'S WRONG WITH MY CODE?

#include <iomanip>
#include <iostream>
#include <string>
#include <vector>
using namespace std;

int main()
{
    int number_test_cases;
    cin >> number_test_cases;

    for (int i = 0; i < number_test_cases; i++)
    {
        long double A, B, C;
        cin >> A >> B >> C;

        cout << std::showbase << std::hex << static_cast<long long int>(A) << endl;

        cout << std::noshowbase << std::dec << std::setw(15) << std::setfill('_') << std::fixed << std::setprecision(2) << std::right << showpos << B << endl;

    cout << std::noshowbase << std::dec << std::uppercase << std::scientific << std::setprecision(9) << noshowpos << C << endl;
}

}

I think the test cases are faulty.

This is actually problematic. Works with certain commands but fails when done step by step because of rounding errors in the test cases (sometimes 0.5 is rounded up and sometimes down).