输入一个整数，输出n行*

n = eval(input("enter a num:"))
for i in range(1, n+1):
    for j in range(n-i+1):
        print(" ", end="")
    for j2 in range(1, 2*i-1+1):
        print("*", end="")
    print()

Result:

enter a num:5
     *
    ***
   *****
  *******
 *********