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What will be the output of the following code:
n = 5
for i in range(1, n+1):
for j in range(i):
print("*", end="")
print()
Options:
a.*
**
***
****
*****
b.*****
****
***
**
*
c.* * * * *
* * * *
* * *
* *
*
d.None of the above
Answer:
Answer by student
a.*
**
***
****
*****
Detailed answer by teachoo
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Let’s go through each of the options and see why they are correct or incorrect.
- Option a.
*
**
***
****
*****
This is the correct answer. We will explain how to get this output in the next steps.
- Option b.
*****
****
***
**
*
This is incorrect . This would be the output if we reversed the order of the range function in the inner loop, i.e. for j in range(i, 0, -1).
- Option c.
* * * * *
* * * *
* * *
* *
*
This is incorrect . This would be the output if we added a space after each asterisk in the print function, i.e. print(“* “, end=””).
- Option d. None of the above: This is incorrect . One of the above options is correct, as we have seen.
Now, let’s see how to get the correct output by following the code step by step.
- The first line of code assigns the value 5 to n:
n = 5
- The second line of code starts a for loop that iterates over the range(1, n+1), which is range(1, 6) or [1, 2, 3, 4, 5].
This means that i will take each of these values one by one: for i in range(1, n+1)
- The third line of code starts another for loop inside the first loop that iterates over the range(i), which is range(0, i) or [0, 1, …, i-1].
This means that j will take each of these values one by one for each value of i: for j in range(i)
- The fourth line of code prints an asterisk without moving to a new line, using the end=“” parameter.
This means that for each value of j, an asterisk will be printed on the same line: print(“*”, end=“”)
- The fifth line of code prints a new line after each iteration of the inner loop.
This means that after printing i asterisks on one line, the cursor will move to the next line: print()
So, what happens when we run this code?
- In the first iteration of the outer loop, i = 1. Then, in the inner loop, j = 0.
So, we print one asterisk on the first line and then move to the next line.
- In the second iteration of the outer loop, i = 2. Then, in the inner loop, j = 0 and j = 1.
So, we print two asterisks on the second line and then move to the next line.
- In the third iteration of the outer loop, i = 3. Then, in the inner loop, j = 0, j = 1 and j = 2.
So, we print three asterisks on the third line and then move to the next line.
- In the fourth iteration of the outer loop, i = 4. Then, in the inner loop, j = 0, j = 1, j = 2 and j = 3.
So, we print four asterisks on the fourth line and then move to the next line.
- In the fifth and final iteration of the outer loop, i = 5. Then, in the inner loop, j = 0, j = 1, j = 2, j = 3 and j = 4.
So, we print five asterisks on the fifth line and then move to the next line.
The output looks like this:
*
**
***
****
*****
So, this matches option a.
So, the correct answer is option a.
*
**
***
****
*****
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