Answer 1

#include <iostream>
using namespace std;

int main() {
int lines;
cout<<"Enter the number of lines"<<endl;
cin>>lines;
for(int i=1;i<=lines;i++)
{
for(int j=1;j<=i;j++)
{
cout<<"*";
}
cout<<endl;
}
return 0;
}

See this:
https://code.sololearn.com/cv85tz9NscD9/#cpp