Built-in Functions
In the competitive programming community, C++ is extremely popular. Most competitive programmers prefer using C++ over Java or Python due to its faster execution speed and widespread usage, among other reasons. Today, we’ll discuss some of the built-in functions available in C++.
Firstly, we replace #include <iostream> with #include <bits/stdc++.h>. This single header file includes all the necessary libraries, so we no longer need to include them individually.
Now let’s explore some commonly used built-in functions often used in competitive programming.
min( )
To find the minimum value, we can use min() function.
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int a = 2, b = 5;
int tmp = min(a, b);
// tmp = 2
max( )
Similarly to find the maximum value, we can use max() function.
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int a = 2, b = 5;
int tmp = max(a, b);
// tmp = 5
floor( )
To get the floor value, we can use floor() function.
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double a = 3.8;
double tmp = floor(a);
// tmp = 3
ceil( )
Similarly to get the ceiling value, we can use ceil() function.
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double a = 3.1;
double tmp = ceil(a);
// tmp = 4
tolower( )
To convert a character to lowercase, we can use tolower() function.
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char ch = 'A';
char tmp = tolower(ch);
// tmp = a
toupper( )
Similarly to convert a character to uppercase, we can use toupper() function.
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char ch = 'a';
char tmp = toupper(ch);
// tmp = A
sqrt( )
To find the square root of any number, we can use sqrt() function.
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double a = 16;
double tmp = sqrt(a);
// tmp = 4
pow( )
To calculate the exponentiation of any number, we can use pow() function.
The result of this function will be ab.
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int a = 2, b = 3;
int tmp = pow(a, b);
// tmp = 8
swap( )
For swapping the values of two variables, we can use swap() function.
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int a = 5, b = 10;
swap(a, b);
// a = 10, b = 5
sort( )
To sort an array in ascending order, we can use sort() function.
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int n = 5;
int arr[n] = { 5,3,4,1,2 };
sort(arr, arr + n);
// arr[n] = { 1,2,3,4,5 }
gcd( )
To find the Greatest Common Divisor (GCD) of two numbers, we can use __gcd() function.
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int a = 6, b = 20;
int gcd = __gcd(a, b);
// gcd = 2
- In addition, to find the Least Common Multiple (LCM) of two numbers, we can use the following method.
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int a = 6, b = 20;
int lcm = (a / __gcd(a, b)) * b;
// lcm = 60