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Python Program to Find Sum of n Numbers



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In this article, you will learn and get code find the sum of n numbers entered by user using a Python program. Here are the list of programs:

For example, if user enters the value of n as 3 and then three numbers as 1, 2, 3. Then the answer will be 1+2+3 or 6.

Sum of n Numbers using for Loop

This program finds the sum of n numbers using for loop. Here the value of n and then n numbers must be entered by user as shown in the program given below:

# Find Sum of n Numbers using for Loop
# ----codescracker.com----

sum = 0
print("Enter the Value of n: ")
n = int(input())
print("Enter " + str(n) + " Numbers: ")
for i in range(n):
    num = int(input())
    sum = sum+num
print("Sum of " + str(n) + " Numbers = " + str(sum))

Here is its sample run:

python program find sum of n numbers

Now supply the input say 6 as value of n and then enter 6 numbers say 10, 20, 30, 40, 50, 60. Here is the sample output with exactly these inputs:

sum of n numbers python

Note - The str() is used to convert from integer to string. Because the + operator in python is used to concatenate only same type's value.

The following code:

for i in range(n):

is used to execute the following block of code:

num = int(input())
sum = sum+num

n number of times starting with value of i from 0 to n-1. For example, if user enters the value of n as 10, then this block of code gets executed 10 times. Using this block, we've received 10 numbers and adds the value and initialized to sum, one by one.

Sum of n Numbers using while Loop

This program does the same job as of previous program, using while loop instead of for:

# ----codescracker.com----

sum = 0
i=0
print(end="Enter the Value of n: ")
n = int(input())
print(end="Enter " + str(n) + " Numbers: ")
while i<n:
    num = int(input())
    sum = sum+num
    i = i+1
print("\nSum of " + str(n) + " Numbers = " + str(sum))

Here is its sample run, with user input 10 as value of n and 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 as 10 numbers:

find sum of n numbers python

Sum of n Numbers using List (Array)

This program find and prints the addition result (or sum) of n numbers entered by user at run-time using list. List is like an array:

# ----codescracker.com----

num = []
sum = 0
print(end="Enter the Value of n: ")
n = int(input())

print(end="Enter " + str(n) + " Numbers: ")
for i in range(n):
    num.insert(i, int(input()))

for i in range(n):
    sum = sum+num[i]

print("\nSum of " + str(n) + " Numbers = " + str(sum))

Here is its sample run with user input, 5 as value of n and 5, 6, 7, 10, 12 as 5 numbers:

sum of n numbers using loop python

The following code:

for i in range(n):

is used to execute following the statement:

num.insert(i, int(input()))

n number of times with i's value from 0 to n-1. Therefore using insert(), the value entered by user gets inserted to the list num[] one by one in this way:

Sum of n Numbers using Function

This is the last program of this article. This program also finds the sum of n numbers as done in previous programs using different-different approaches. Like those, this program also approach in an another way (using a user-defined function) to do the same task:

# ----codescracker.com----

def SumOfNNums(arr, tot):
    s = 0
    for i in range(tot):
        s = s+arr[i]
    return s

num = []
print(end="Enter the Value of n: ")
n = int(input())
print(end="Enter " + str(n) + " Numbers: ")
for i in range(n):
    num.insert(i, int(input()))

sum = SumOfNNums(num, n)
print("\nSum of " + str(n) + " Numbers = " + str(sum))

Here is its sample run with user input, 3 as value of n and 20, 30, 10 as 3 numbers:

sum of n numbers using function python

With following statement:

sum = SumOfNNums(num, n)

we've called the function SumOfNNums(). So after executing this statement, the function gets executed and the value return by function is the result, that is the summation of n numbers entered by user. So the return value gets initialized to sum, and its value gets printed.


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