clearing console in cpp - c++

Question

system("cls") doesnt work, it finishes the program without printing anything.
the program works without it but doesnt look nice in the console without all the previous prints cleared. I've tried putting the command in different places but it doesnt matter where i put it the program finishes instantly.
#include <iostream>
#include <math.h>
#include <windows.h>
#include <stdlib.h>
using namespace std;
float c, temp, eq;
char odp = 't';
int main()
{
do
{
cout << "Choose from what value you'd like to convert." << endl;
cout << "Celsius = 1 ; Fahrenheit = 0" << endl;
cin >> c;
if (c==1)
{
cout << "Insert Celsius value: ";
cin >> temp;
eq = temp * 1.8 + 32;
cout << "It is " << eq << " degrees Fahrenheit." << endl;
cout << "If you want to continue converting please insert: t" << endl;
cin >> odp;
}
else if (c==0)
{
cout << "Insert Fahrenheit value: ";
cin >> temp;
eq = (temp * 1.8) - 32;
cout << "It is " << eq << " degrees Celsius." << endl;
cout << "If you want to continue converting please insert: t" << endl;
cin >> odp;
}
else
{
cout << "Please choose correctly" << endl;
}
}
while(odp = 't');
return 0;
}
how i put the command and it finishes the whole program instantly
#include <iostream>
#include <math.h>
#include <windows.h>
#include <stdlib.h>
using namespace std;
float c, temp, eq;
char odp = 't';
int main()
{
do
{
cout << "Choose from what value you'd like to convert." << endl;
cout << "Celsius = 1 ; Fahrenheit = 0" << endl;
cin >> c;
if (c==1)
{ system("cls") //here
cout << "Insert Celsius value: ";
cin >> temp;
eq = temp * 1.8 + 32;
cout << "It is " << eq << " degrees Fahrenheit." << endl;
cout << "If you want to continue converting please insert: t" << endl;
cin >> odp;
}
else if (c==0)
{
cout << "Insert Fahrenheit value: ";
cin >> temp;
eq = (temp * 1.8) - 32;
cout << "It is " << eq << " degrees Celsius." << endl;
cout << "If you want to continue converting please insert: t" << endl;
cin >> odp;
}
else
{
cout << "Please choose correctly" << endl;
}
}
while(odp = 't');
return 0;
}
i really dont know, thanks for the replies