How to make this with c++ ?

Question

1
12
123
1234
12345=15

Answer 1

assume you got the necessary thinga imported and the main function

cin>>row;
for (int i=0;i<row;i++){
for (int j=1;j<i+2;j++){
cout<<j;}
if (i<row-1){cout<<"\n";}
else{cout<<"="<<i*(i+1)/2;}
}

Answer 2

@Pegasus thank you!

Answer 3

One small correction: The "=" sign

Answer 4

Hey mark the other one best answer!
I edited the code!