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    Python Program to Find the Largest of Three Numbers

    easyif / elsePython

    A favourite practical question because it tests whether you can build a decision with more than two branches.

    The question

    Read three different integers (one per line) and print the largest of them. Use if/elif/else — do not use max().

    The code

    program.py

    a = int(input())
b = int(input())
c = int(input())
if a > b and a > c:
    largest = a
elif b > c:
    largest = b
else:
    largest = c
print("Largest =", largest)
    Try it Yourself »

    Input

    67
19
34

    Output

    Largest = 67

    How it works

    1. 1First check whether a is bigger than both b and c — the and operator needs both comparisons to be true.
    2. 2If a is not the largest, the answer must be b or c, so a single comparison b > c decides it.
    3. 3Store the winner in largest and print it once at the end.

    Common mistakes

    • Writing if a > b > c — it only proves a > b and b > c, and misses the case where c > b.
    • Using max() when the question says to use if-else — examiners take marks for that.

    Largest of three numbers using max()

    The shortest way. Use it when the question does not insist on if-else — max() accepts any number of values.

    program.py

    a = int(input())
b = int(input())
c = int(input())
print("Largest =", max(a, b, c))
    Try it Yourself »

    Input

    12
45
7

    Output

    Largest = 45

    Largest of three numbers using nested if

    First decide between a and b, then compare the winner with c. Some question papers ask for this form by name.

    program.py

    a = int(input())
b = int(input())
c = int(input())
if a > b:
    if a > c:
        largest = a
    else:
        largest = c
else:
    if b > c:
        largest = b
    else:
        largest = c
print("Largest =", largest)
    Try it Yourself »

    Input

    7
88
23

    Output

    Largest = 88

    Questions students ask

    How do you find the largest of three numbers in Python without max()?
    Use if-elif-else: if a is greater than both b and c, a is the largest; otherwise compare b with c. That is the program at the top of this page.
    What happens if two of the numbers are equal?
    The program still prints the right value. With 5, 5 and 3 the first condition is false, b > c is true, and it prints 5.

    Now solve a similar question yourself

    A new Python question every time, checked instantly.

    Practice questions

    Preparing for NIELIT O Level?

    This program is the kind asked in the M3 (Python) theory paper and the PR-3 practical exam.

    More in if / else

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