CHAPTER 3: THE LOOP CONTROL STRUCTURE

EXAMPLE ON PAGE:89-90

In [1]:
 
count=1
while count<=3:                                    #while loop codition check
    print "Enter values of p,n and r"
    p=eval(raw_input())
    n=eval(raw_input())
    r=eval(raw_input())
    si=p*n*r/100
    print "Simple interest=Rs.%f" % (si)
    count=count+1                                  #increment

Enter values of p,n and r
1000
5
13.5
Simple interest=Rs.675.000000
Enter values of p,n and r
2000
5
13.5
Simple interest=Rs.1350.000000
Enter values of p,n and r
3500
5
3.5
Simple interest=Rs.612.500000

EXAMPLE ON PAGE:92

In [ ]:
 
i=1
while i<=10:
    print "%d\n" % (i)                      #there is no increment/decrement thats why indefinite loop

EXAMPLE ON PAGE:93

In [2]:
 
i=1
while i<=10:
    print "\n" ,i
    i=i+1

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EXAMPLE ON PAGE:93

In [3]:
 
i=5
while i>=1:
    print "Make the computer literate!\n"
    i=i-1

Make the computer literate!

Make the computer literate!

Make the computer literate!

Make the computer literate!

Make the computer literate!

EXAMPLE ON PAGE:93

In [4]:
 
a=10.0
while a<=10.5:
    print "Raindrops on roses..."
    print "...and whiskers on kittens\n"
    a=a+0.1

Raindrops on roses...
...and whiskers on kittens

Raindrops on roses...
...and whiskers on kittens

Raindrops on roses...
...and whiskers on kittens

Raindrops on roses...
...and whiskers on kittens

Raindrops on roses...
...and whiskers on kittens

Raindrops on roses...
...and whiskers on kittens

EXAMPLE ON PAGE:94

In [ ]:
 
i=1
while i<=32767:                                  #print numbers from 1 to 32767
    print "%d\n" ,i                       
    i=i+1

EXAMPLE ON PAGE:95

In [5]:
 
i=1 
while i<=10:
    print i
    i=i+1

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10

EXAMPLE ON PAGE:96

In [6]:
 
i=1
while i<=10:
    print "\n" ,i
    i+=1                                       #increment short hand operator

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EXAMPLE ON PAGE:98

In [7]:
 
for count in range(1,4,1):                          #for loop
    print "Enter values of p,n and r"
    p=eval(raw_input())
    n=eval(raw_input())
    r=eval(raw_input())
    si=p*n*r/100
    print "Simple Interest=Rs.%f" % (si)

Enter values of p,n and r
1000
5
13.5
Simple Interest=Rs.675.000000
Enter values of p,n and r
2000
5
13.5
Simple Interest=Rs.1350.000000
Enter values of p,n and r
3500
5
3.5
Simple Interest=Rs.612.500000

EXAMPLE ON PAGE:101

In [8]:
 
for i in range(1,11,1):
    print "%d\n" % (i)

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EXAMPLE ON PAGE:101

In [9]:
 
for i in range(1,11):
    print "\n" ,i
    i=i+1

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EXAMPLE ON PAGE:101

In [10]:
 
i=1
for i in range(i,11,1):
    print "%d\n" % (i)

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EXAMPLE ON PAGE:102

In [11]:
 
i=1
for i in range(i,11):
    print "%d\n" % (i)
    i=i+1

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EXAMPLE ON PAGE:103

In [12]:
 
for r in range(1,4,1):                              #outer loop
    for c in range(1,3,1):                          #inner loop    
        sum=r+c
        print "r=%d c=%d sum=%d\n" % (r,c,sum)

r=1 c=1 sum=2

r=1 c=2 sum=3

r=2 c=1 sum=3

r=2 c=2 sum=4

r=3 c=1 sum=4

r=3 c=2 sum=5

EXAMPLE ON PAGE:104-105

In [1]:
 
while(1):                                             #do-while loop is not present in python
    print "Enter a number"
    num=eval(raw_input())
    print "square of %d is %d\n" % (num,num*num)
    print "Want to enter another number y/n"
    another=raw_input()
    if(another!='y'):
        break

Enter a number
5
square of 5 is 25

Want to enter another number y/n
y
Enter a number
7
square of 7 is 49

Want to enter another number y/n
n

EXAMPLE ON PAGE:105

In [13]:
 
another='y'
for i in range(1,1000):                                #check if another is in word
    if another=='y':
        print "Enter a number"
        num=eval(raw_input())
        print "square of %d is %d\n" % (num,num*num)
        print "Want to enter another number y/n"
        another=raw_input()

Enter a number
5
square of 5 is 25

Want to enter another number y/n
y
Enter a number
7
square of 7 is 49

Want to enter another number y/n
n

EXAMPLE ON PAGE:105-106

In [14]:
 
another='y'
while(another=='y'):
    print "Enter a number"
    num=eval(raw_input())
    print "square of %d is %d\n" % (num,num*num)
    print "Want to enter another number y/n"
    another=raw_input()

Enter a number
5
square of 5 is 25

Want to enter another number y/n
y
Enter a number
7
square of 7 is 49

Want to enter another number y/n
n

EXAMPLE ON PAGE:106

In [15]:
 
print "Enter a number"
num=eval(raw_input())
i=2
while i<=num-1:
    if num%i==0:
        print "Not a prime number\n"
        break                                           #exit the loop
    i+=1
if i==num:
    print "Prime number\n"

Enter a number
11
Prime number

EXAMPLE ON PAGE:107

In [16]:
 
i=1
j=1
while (i<=100):
    i+=1
    while (j<=200):
        j+=1
        if (j==150):
            break                        #it will terminate the inner loop only
        else:
            print "%d %d\n" % (i,j)

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EXAMPLE ON PAGE:108

In [17]:
 
for i in range(1,3,1):
    for j in range(1,3,1):
        if i==j:
            continue                #it will again send back to loop without executing succeeding statements
        print "%d %d\n" % (i,j)

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