## 5. Using while Loops

print("-"*10+"Check if class is needed"+"-"*10)
ans=input("Is there a class today? y/n")
while ans=="y":
    print("Class is required")
    ans=input("Is there a class today? y/n")

print("-"*10+"Sum of 1 to 100"+"-"*10)
s=0
i=1
while i<=100:
    s+=i
    i+=1
print(s)

6. Simulating User Login with while Loop

i=0 while i<3: user_name=input("Enter your username:") pwd=input("Enter your password") if user_name=="ty" and pwd=="666666": print("Logging in...") i=4 else: if i<=2: print("Username or password incorrect, you have ",2-i," attempts left") i+=1

if i==3: print("All three login attempts failed")

## 7. Nested Loops for Printing Shapes

print("-"*10+"Print a 3x4 matrix"+"-"*10)
for i in range(1,4):
    for j in range(1,5):
        print("*",end="")
    print()

print("-"*10+"Print a right triangle with 5 rows"+"-"*10)
for i in range(1,6):
    for j in range(1,i+1):
        print("*",end="")
    print()

print("-"*10+"Print an inverted right triangle with 5 rows"+"-"*10)
for i in range(1,6):
    for j in range(1,7-i):
        print("*",end="")
    print()

print("-"*10+"Print an inverted isosceles triangle with 5 rows"+"-"*10)
for i in range(1,6):
    for j in range(1,6-i):
        print(" ",end="")
    for k in range(1,i*2):
        print("*",end="")
    print()

8. Nested Loops for Printing a Diamond

row=eval(input("Enter the number of rows:")) while row%2==0: print("Please enter an odd number!") row = eval(input("Enter the number of rows:")) top_row=(row+1)//2

for i in range(1,top_row+1): for j in range(1,top_row+1-i): print(" ",end="") for k in range(1,i2): print("",end="") print()

bottom_row=row//2 for i in range(1,bottom_row+1): for j in range(1,i+1): print(" ",end="") for k in range(1,2bottom_row-i2+2): print("*",end="") print()

## 9. Nested Loops for Printing an Hollow Diamond

row=eval(input("Enter the number of rows:"))
while row%2==0:
    print("Please enter an odd number!")
    row = eval(input("Enter the number of rows:"))
top_row=(row+1)//2

for i in range(1,top_row+1):
    for j in range(1,top_row+1-i):
        print(" ",end="")
    for k in range(1,i*2):
        if k<1 or k>i*2-1:
            print("*", end="")
        else:
            print(" ", end="")
    print()

bottom_row=row//2
for i in range(1,bottom_row+1):
    for j in range(1,i+1):
        print(" ",end="")
    for k in range(1,2*bottom_row-i*2+2):
        if k<1 or k<2*bottom_row-i*2+2-1:
            print("*", end="")
        else:
            print(" ", end="")
    print()

10. Using break and contiune

break

s=0 i=0 while i<20: s+=i if s>100: print("The current number when sum exceeds 100 is",i) break i+=1

s=0 for i in range(1,20): s+=i if s>100: break print("The current number when sum exceeds 100 is",i)

continue

i=0 s=0 while i<100: if i%2==1: i+=1 continue s+=i i+=1