# Chapter 5: Program looping¶

### Program 5.1, Page number: 43¶

In [1]:
triangularNumber = 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8;

print("The eighth triangular number is {0}".format(triangularNumber))

The eighth triangular number is 36


### Program 5.2, Page number: 44¶

In [2]:
triangularNumber=0

for i in range (201):
triangularNumber=triangularNumber+i

print("The 200th triangular number is {0}".format(triangularNumber))

The 200th triangular number is 20100


### Program 5.3, Page number: 47¶

In [3]:
print("TABLE OF TRIANGULAR NUMBERS\n\n")
print(" n          Sum from 1 to n\n")
print("---        -----------------\n")

triangularNumber=0

for i in range (1,11):
triangularNumber=triangularNumber+i
print(" {0}                  {1}\n".format(i,triangularNumber))

TABLE OF TRIANGULAR NUMBERS

n          Sum from 1 to n

---        -----------------

1                  1

2                  3

3                  6

4                  10

5                  15

6                  21

7                  28

8                  36

9                  45

10                  55



### Program 5.4, Page number: 51¶

In [5]:
triangularNumber=0
number=10                                #number=input("What triangular number do you want?")

for n in range (1,(number+1)):
triangularNumber+=n

print("triangular number {0} is {1}".format(number,triangularNumber))

triangular number 10 is 55


### Program 5.5, Page number: 53¶

In [7]:
for counter in range(1,6):                     #Outer Loop
number=12                              #input("what triangular number do you want? ")

triangularNumber=0                     #Variable Decaration

for n in range (1,(number+1)):         #Inner Loop
triangularNumber+=n

#Result
print("Triangular Number {0} is {1}".format(number,triangularNumber))

Triangular Number 12 is 78
Triangular Number 12 is 78
Triangular Number 12 is 78
Triangular Number 12 is 78
Triangular Number 12 is 78


### Program 5.6, Page number: 56¶

In [9]:
count=1

while (count<=5):
print("{0}\n".format(count))     #Result
count+=1

1

2

3

4

5



### Program 5.7, Page number: 58¶

In [11]:
print("Please type in two nonnegative integers.")
u=8                                               #u=input()
v=14                                              #v=input()

while(v!=0):
temp=u%v
u=v
v=temp

print("Their greatest common divisor is {0}\n".format(u))

Please type in two nonnegative integers.
Their greatest common divisor is 2



### Program 5.8, Page number: 60¶

In [13]:
import sys

while(number!=0):
right_digit=number%10
sys.stdout.write("{0}".format(right_digit))
number=number/10

print("\n")

311



### Program 5.9, Page number: 61¶

In [14]:
import sys


824