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Lição 1. Entering and output of data
Dificuldade:
Tarefa«Triângulo de Heron»
💻 Python
escreva um programa que calcula a área do triângulo a partir de três lados usando a fórmula de Heron.
nA fórmula de Heron é assim:
n
onde & nbsp; a , & nbsp; b , & nbsp; c & nbsp; & mdash; os comprimentos dos lados do triângulo, e & nbsp; p & mdash; seu semiperímetro, que é calculado pela fórmula:
p = (a+b+c)/2
Formato de entrada
Uma linha contendo três números (comprimentos dos lados do triângulo & nbsp;
Formato de saída
Um número & mdash; área de um triângulo. O resultado pode ser um número fracionário.
Exemplo
Entrada
3 4 5
Saída
6.0
Dica
Reading multiple variables from a single line
Python has a convenient way to count multiple variables in a single input() call. This is especially useful in tasks where data is served in a single line, separated by some character (most often a space).
How it works:
input()reads the entire string, for example"20 30".- The
.split()method "cuts" this string by the specified separator (by default, by a space) and creates a list of strings:['20', '30']. - Function
map(int, ...)applies theint(integer conversion) function to each element of this list. The result is a specialmapobject. - Finally, Python "unpacks" this object using the variables
aandb.
Example: Input:
20 30
Reading:
a, b = map(int, input().split()) # float can be used if fractional numbers are needed
print(a, b) # outputs 20 30
print(type(a)) # outputs <class 'int'>
Useful tips:
- If the numbers are separated not by a space, but, for example, by a comma (input:
20,30), specify this in thesplit()method:input().split(','). - Make sure that the number of variables to the left of
=matches the number of values in the row. If they do not match, the program will return the errorValueError.
Three types of division
There are three different division operators in Python, and each one serves a different purpose.
-
/Ordinary (real) division This operator always returns a fractional number (float) as a result, even if the numbers are completely divisible.a = 27 b = 10 print(a/5) # outputs 5.4 print(b/2) # outputs 5.0 (note, not 5, but 5.0) -
//Integer division This operator performs division and discards the fractional part, returning an integer (int). It sort of answers the question "how many times does one number fit entirely into another?".a = 27 print(a// 5) # outputs 5 (because 5 is placed in 27 five full times) -
%The remainder of the division (modulo division) This operator returns what is "left" after the integer division.a = 27 print(a %5) # outputs 2 Logic: the nearest number to 27 that is divisible by 5 without remainder is 25. # Difference: 27-25 = 2.
Practical application %: The most common use of the % operator is the parity check. Any even number is divisible by 2 without remainder, and an odd number is divisible by 1.
a = 27
b = 14
print(f"Is {a} an odd number? The remainder of the division by 2: {a %2}") # outputs 1
print(f"Is {b} an even number? The remainder of the division by 2: {b %2}") # outputs 0
Exponentiation
To exponentiate a number in Python, the ** operator is used.
a = 2
b = 3
print(a**3) # outputs 8 (2 to the power of 3)
print(b**2) # outputs 9(3 to the power of 2)
Useful tips:
- To extract the square root, you can raise the number to the power of
0.5.print(9**0.5) # outputs 3.0 - There is also a built-in function
pow(a,b)that does the same thing asa**b.print(pow(2, 3)) # outputs 8
print() function and string formatting
The print() function outputs data to the screen. Simply adding strings and variables using + is inconvenient, since numbers need to be constantly converted into strings using str(). Modern Python offers more elegant ways.
f-strings (f-strings) - recommended method: This is the most modern, fastest and most readable way. The string is preceded by the letter f, and variables or expressions are specified inside curly braces {}.
name = "Alice"
age = 30
print(f"Name: {name}, Age: {age}")
# Output: Name: Alice, Age: 30
Advantage: you can perform operations right inside the brackets.
print(f"In a year she will be {age + 1}")
# Conclusion: In a year she will be 31
The .format() method is an older, but still relevant method: Empty curly braces {} are placed in the line, and after the line the .format() method is called, to which variables are passed.
name = "Alice"
age = 30
print("Name: {}, Age: {}".format(name, age))
# Output: Name: Alice, Age: 30
Useful tips for print():
- Separator
sep: By default,printseparates its arguments with a space. This can be changed.print(1, 2, 3, sep="-") # outputs 1-2-3 - Ending
end: By default,printadds a newline after the output\n. This can also be changed so that the following print outputs continue on the same line.print("Hello,", end="") print("world!") # The output will be in one line: Hello, world!
main.py
Teste 1
Teste 2
Teste 3
Teste 4
Teste 5
Teste 6
Teste 7
Teste 8
Teste 9
Teste 10
Solução do desenvolvedor
# Считываем три стороны треугольника из одной строки
a, b, c = map(float, input().split())
# Вычисляем полупериметр (p)
p = (a + b + c) / 2
# Вычисляем площадь по формуле Герона
# Используем ** 0.5 для извлечения квадратного корня
area = (p * (p - a) * (p - b) * (p - c)) ** 0.5
# Выводим результат
print(area)
