Main.cc: In function ‘int main()’:
Main.cc:12:22: error: lvalue required as left operand of assignment
pi+=(-1)^i/(2*i+1);}
^
Main.cc:13:28: error: lvalue required as left operand of assignment
pi = round(pi * 100000)/ 100000;
^~~~~~
Main.cc:8:8: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
scanf("%d",&n);
~~~~~^~~~~~~~~