using namespace std;
int main()
{
int t,i=1;
cin>>t;
while(i>=t)
{
int l, k; long long s=0;
cin>>l>>k;
if(l>=k)
{
s=(l-k+1);
s=(s*(s+1))/2;
cout<<“Case”<<i<<":"<<s<<endl;
}
else
cout<<“Case”<<i<<":"<<0<<endl;
i++;
}
return 0;
}
using namespace std;
int main()
{
int t,i=1;
cin>>t;
while(i>=t)
{
int l, k; long long s=0;
cin>>l>>k;
if(l>=k)
{
s=(l-k+1);
s=(s*(s+1))/2;
cout<<“Case”<<i<<":"<<s<<endl;
}
else
cout<<“Case”<<i<<":"<<0<<endl;
i++;
}
return 0;
}
while (i>=t)
looks like it should be
while (i<=t)
And the spacing of your output is not quite right. Make it match the sample exactly.