The program is an illustration of loops
<h3>What are loops?</h3>
Loops are program statements that are used to perform repetition
<h3>The main program</h3>
The program written in Python, where comments are used to explain each line is as follows:
#This initializes sum to 0
summ = 0
#This gets input for the first number
num = int(input())
#This is repeated while num is not -1
while num!= -1:
#This calculates the sum
summ+=num
#This gets input for the num
num = int(input())
#This prints the sum
print(summ)
Read more about loops at:
brainly.com/question/16397886
The graph does not represent a function