Chapter 5- Control Flow

Example-age1.cpp, Page no-153

age=int(raw_input("Enter your age: "))
if(age>12 and age<20):
    print "you are a teen-aged person. good!"

Enter your age: 15
you are a teen-aged person. good!

Example-age2.cpp, Page no-154

age=int(raw_input("Enter your age: "))
if(age<0):
    print "I am sorry!"
    print "age can never be negative"
if(age>12 and age<20):
    print "you are a teen-aged person. good!"

Enter your age: -10
I am sorry!
age can never be negative

Example-large.cpp, Page no-155

big=float
a, b, c=[float(x) for x in raw_input("Enter three floating-point numbers: ").split()] #taking input in single line separated by white space
big=a
if(b>big):
    big=b
if(c>big):
    big=c
print "Largest of the three numbers =", big

Enter three floating-point numbers: 10.2 15.6 12.8
Largest of the three numbers = 15.6

Example-age3.cpp, Page no-156

age=int(raw_input("Enter your age: "))
if(age>12 and age<20):
    print "you are a teen-aged person. good!"
else:
    print "you are not a teen-aged person."

Enter your age: 15
you are a teen-aged person. good!

Example-lived.cpp, Page no-157

years=float(raw_input("Enter your age in years: "))
if(years<0):
    print "I am sorry! age can never be negative"
else:
    secs=years*365*24*60*60
    print "You have lived for %.4g seconds" %(secs)

Enter your age in years: 25
You have lived for 7.884e+08 seconds

Example-age4.cpp, Page no-158

age=int(raw_input("Enter your age: "))
if(age>12 and age<20):
    print "you are a teen-aged person. good!"
else:
    if(age<13):
        print "you will surely reach teen-age."
    else:
        print "you have crossed teen-age!"

Enter your age: 25
you have crossed teen-age!

Example-count1.cpp, Page no-159

n=int(raw_input("How many integers to be displayed: "))
for i in range(n):
    print i

How many integers to be displayed: 5
0
1
2
3
4

Example-sumsq1.cpp, Page no-160

Sum=0
sum_of_squares=0
for i in range(2, 31, 2):
    Sum+=i
    sum_of_squares+=i*i
print "Sum of first 15 positive even numbers =", Sum
print "Sum of their squares =", sum_of_squares

Sum of first 15 positive even numbers = 240
Sum of their squares = 4960

Example-sumsq2.cpp, Page no-161

Sum=0
sum_of_squares=0
for i in range(30, 0, -2):
    Sum+=i
    sum_of_squares+=i*i
print "Sum of first 15 positive even numbers =", Sum
print "Sum of their squares =", sum_of_squares

Sum of first 15 positive even numbers = 240
Sum of their squares = 4960

Example-noinit.cpp, Page no-162

i=1
for i in range(i, 11):
    print i*5,

5 10 15 20 25 30 35 40 45 50

Example-pyramid.cpp, Page no-163

n=int(raw_input("Enter the number of lines: "))
for p in range(1, n+1):
    for q in range(1, n-p+1):
        print "\t",
    m=p
    for q in range (1, p+1):
        print "\t", m,
        m+=1
    m=m-2
    for q in range(1, p):
        print "\t", m,
        m-=1
    print ''

Enter the number of lines: 5
					1 
				2 	3 	2 
			3 	4 	5 	4 	3 
		4 	5 	6 	7 	6 	5 	4 
	5 	6 	7 	8 	9 	8 	7 	6 	5 

Example-count2.cpp, Page no-164

n=int(raw_input("How many integers to be displayed: "))
i=0
while i<n:
    print i
    i+=1

How many integers to be displayed: 5
0
1
2
3
4

Example-average1.cpp, Page no-164

Sum=0
count=0
print "Enter the marks, -1 at the end..."
marks=int(raw_input())
while marks!=-1:
    Sum+=marks
    count+=1
    marks=int(raw_input())
average=Sum/count
print "The average is", average    

Enter the marks, -1 at the end...
80
75
82
74
-1
The average is 77

Example-bin2deci.cpp, Page no-165

decimal=0
position=0
binary=int(raw_input("Enter the binary number: "))
while binary:
    digit=binary%10
    decimal+=digit<<position
    binary/=10
    position+=1
print "Its decimal equivalent =", decimal

Enter the binary number: 111
Its decimal equivalent = 7

Example-count3.cpp, Page no-166

n=int(raw_input("How many integers to be displayed: "))
i=0
while 1: #do while loop
    print i
    i+=1
    if i>=n:
        break

How many integers to be displayed: 5
0
1
2
3
4

Example-dowhile.cpp, Page no-167

while 1: #do-while loop
    inchar=raw_input("Enter your sex (m/f): ")
    if(inchar=='m' or inchar=='f'):
        break
if inchar=='m':
    print "so you are male. good!"
else:
    print "so you are female. good!"

Enter your sex (m/f): d
Enter your sex (m/f): b
Enter your sex (m/f): m
so you are male. good!

Example-pa1.cpp, Page no-167

rev=0
num=int(raw_input("Enter the number: "))
n=num
while 1:
    digit=num%10
    rev=rev*10 + digit
    num/=10
    if num==0:
        break
print "Reverse of the number =", rev
if n==rev:
    print "The number is a palindrome"
else:
    print "The number is not a palindrome"

Enter the number: 121
Reverse of the number = 121
The number is a palindrome

Example-average2.cpp, Page no-169

Sum=0
count=0
print "Enter the marks, -1 at the end..."
while 1:
    marks=int(raw_input())
    if marks==-1:
        break
    Sum+=marks
    count+=1
average=Sum/count
print "The average is", average    

Enter the marks, -1 at the end...
80
75
82
74
-1
The average is 77

Example-sex2.cpp, Page no-171

ch=raw_input("Enter your sex (m/f): ")
if ch=='m':
    print "So you are male. good!"
elif ch=='f':
    print "So you are female. good!"
else:
    print "Error: Invalid sex code!"

Enter your sex (m/f): m
So you are male. good!

Example-calc.cpp, Page no-172

print "------------------Basic Calculator------------------"
print "Choose an option:"
print "Add"
print "Subtract"
print "Multiply"
print "Divide"
ch=raw_input()
num1, num2=[int(x) for x in raw_input("Enter the value of the operands: ").split()]
if ch=='1':
    print num1+num2
elif ch=='2':
    print num1-num2
elif ch=='3':
    print num1*num2
elif ch=='4':
    print num1/num2
else:
    print "Incorrect choice: "

------------------Basic Calculator------------------
Choose an option:
Add
Subtract
Multiply
Divide
1
Enter the value of the operands: 22 33
55

Example-sumpos.cpp, Page no-174

total=0
while 1:
    num=int(raw_input("Enter a number (0 to quit): "))
    if num==0:
        print "end of data entry."
        break
    if num<0:
        print "skipping this number."
        continue
    total+=num
print "Total of all +ve numbers is ", total

Enter a number (0 to quit): 10
Enter a number (0 to quit): 20
Enter a number (0 to quit): -5
skipping this number.
Enter a number (0 to quit): 10
Enter a number (0 to quit): 0
end of data entry.
Total of all +ve numbers is  40

Example-jump.cpp, Page no-175

total=0
while 1:
    num=int(raw_input("Enter a number (0 to quit): "))
    if num==0:
        print "end of data entry."
        print "Total of all +ve numbers is", total #no goto in python
        break
    if num<0:
        print "skipping this number."
        continue
    total+=num

Enter a number (0 to quit): 10
Enter a number (0 to quit): 20
Enter a number (0 to quit): -5
skipping this number.
Enter a number (0 to quit): 10
Enter a number (0 to quit): 0
end of data entry.
Total of all +ve numbers is 40

Example-age5.cpp, Page no-177

age=int(raw_input("Enter your age: "))
if(age>12 and age<20):
    pass
print "you are a teen-aged person. good!"

Enter your age: 50
you are a teen-aged person. good!

Example-agecmp.cpp, Page no-177

myage=25
print "Hi! my age is ", myage
yourage=int(raw_input("What is your age? "))
if myage==yourage:
    print "We are born on the same day. Are we twins!"

Hi! my age is  25
What is your age? 25
We are born on the same day. Are we twins!

Example Page no-178

l1=int(raw_input("Enter the lower limit: "))
l2=int(raw_input("Enter the higher limit: "))
print "The prime numbers between", l1, "and", l2, "are: ",
for i in range(l1, l2+1):
    if i<=3:
        print i,"\t",
    else:
        for j in range(2, i/2+1):
            if(i%j==0):
                break
        if(i%j==0):
            continue #no goto
        print i, "\t",

Enter the lower limit: 1
Enter the higher limit: 100
The prime numbers between 1 and 100 are:  1 	2 	3 	5 	7 	11 	13 	17 	19 	23 	29 	31 	37 	41 	43 	47 	53 	59 	61 	67 	71 	73 	79 	83 	89 	97