Absolute value function in C language

1. Absolute value of plastic surgery:
abs function
Header file: include<> or include<>

int abs(int n)           //The parameters and return values ​​are both int type

#include<>
#include<>

int main()
{
	int n = -20;
	n = abs(n);
	printf("%d",n);
	return 0;
}

Output sample:

20

2. Double precision floating point absolute value:
Fabs function
Header file: include<> or include<>

double fabs(double n)      //The parameters and return values ​​are double

#include<>
#include<>

int main()
{
	double n = -3.14159;
	n = fabs(n);
	printf("%lf",n);
	return 0;
}

Output sample:

3.141590

3. Absolute value of long integer:
labs function
Header file: include<> or include<>

long labs(long n)          //The parameters and return values ​​are long int type

#include<>
#include<>

int main()
{
	long n = -1234567891;
	n = labs(n);
	printf("%ld",n);
	return 0;
}

Output sample:

1234567891