6. Please write a program that requests a positive 6-digit integer, and prints out the sum of these five digits on the screen. For example, if the input number is 123456, the result would be 1+2+3+4+5+6=21. 7. Please write a program to answer the question. The world population reached 6.83 billion people in January 2010 and was growing at the rate of 1.12% each year. Assuming that the population will continue to grow at the same rate, when will the population reach 30 billion