CONTROL STATEMENTS
===================

PYTHON PROGRAMS
================
STATEMENT BY STATEMENT EXECUTION IS APPLICABLE FOR PYTHON PROGRAMS
THIS IS CALLED AS "SEQUENTIAL EXECUTION".

WHY CONTROL STATEMENTS
======================
1) TO MAKE EXECUTE THE SELECTED BLOCK OF STATEMENTS ONLY
2) TO MAKE EXECUTE SELECTED THE BLOCK OF CODE FOR SEVERAL NUMBER OF TIMES REPEATEDLY.
3) TO PAUSE/STOP EXECUTING THE BLOCK OF CODE

TYPES OF CONTROL STATEMENTS
============================
3-TYPES:
	1) CONDITIONAL STATEMENTS
	2) ITERATIVE STATEMENTS
	3) TRANSFER STATEMENTS

1) CONDITIONAL STATEMENTS
=========================
==> ALSO CALLED AS "SELECTION STATEMENTS"
==> TO MAKE EXECUTE ONLY SELECTED BLOCK OF CODE IN A PROGRAM, CONDITIONAL STATEMENTS ARE USED.
==> THREE TYPES OF CONDITIONAL STATEMENTS:
	1) IF STATEMENT
	2) IF ELSE STATEMENT
	3) NESETED IF ELSE STATEMENT
	4) IF ELIF ELSE STATEMENT

1) IF STATEMENT
===============
if is a keyword
we can use if keyword to define the if statement.
Syntax:
	if condition:
		statement-1
		statement-2
	statement-3
	statement-4

Drawback:
=========
1) if a condition is "True".
the program can execute with sequential execution process.
2) if a condition is "False"
if block statements cannot execute.

number = int(input("Enter a number:"))

if number < 0:  # -7
    number = -number    # negative number is changing to positive number 7
    print("The Number after the sign change is = ",number) # 7
print("The Given number = ",number) # 7

=============================
n = False

if n:
    print("Hi")
    print("Hello")
print("Good Morning")

========================================================

2) IF ELSE STATEMENT
====================
here: else ===> keyword

Syntax:
	if condition:
		statement-1
		statement-2
	else:
		statement-3
		statement-4

if condition == "True"
==> only if block statements can execute
if condition == "False"
==> only the else block statements can execute.

# WAP TO CHECK WHETHER THE GIVEN NUMBER IS EVEN NUMBER OR ODD NUMBER.

num = int(input("Enter a number:"))

# even number ==> number / 2: remainder == 0
# odd number ==> number / 2: remainder == 1

if num % 2 == 0:
    print(num,"is an even number.")
else:
    print(num,"is an odd number.")
===========================================================

Nested if else:
==============
Syntax:
	if condition1:
		if condition2:
			statement-1
			statement-2
		else:
			statement-3
			statement-4
	else:
		if condition3:
			statement-5
			statement-6
		else:
			statement-7
			statement-8

# WAP TO FIND THE BIGGEST NUMBER AMONG THREE INTEGERS.

th1 = int(input("Enter a value:")) # 7
th2 = int(input("Enter a value:")) # 9
th3 = int(input("Entre a value:"))  # 97

if th1 > th2:
    if th1 > th3:
        biggest = th1
    else:
        biggest = th3
else:
    if th2 > th3:
        biggest = th2
    else:
        biggest = th3
print("The Biggest number = ",biggest)

=============================================

4) if elif else ladder
=====================
Syntax:
	if condition1:
		statements
	elif condition2:
		statements
	elif condition3:
		statements
	else:
		statements

s1 = int(input("Enter marks:"))
s2 = int(input("Enter marks:"))
s3 = int(input("Enter marks:"))
s4 = int(input("Entre marks:"))

total = s1 + s2 + s3 + s4

percentage = total // 4

if percentage >= 85:
    grade = 'A'
elif percentage >= 70 and percentage < 85:
    grade = 'B'
elif percentage >= 55 and percentage < 70:
    grade = 'C'
elif percentage >= 40 and percentage < 55:
    grade = 'D'
else:
    grade = 'F'

print("The Total Marks of the student = ",total)
print("The Percentage of the student = ",percentage)
print("The Grade of the student = ",grade)