library function programe

1. #include <iostream>
2. #include <cmath>
3. using namespace std;
5. int main()
6. {
7. double x = 10.25, result;
8. result = sqrt(x);
9. cout << "Square root of " << x << " is " << result << endl;
11. return 0;
12. }

The pow() function computes a base number raised to the power of exponent number.

#include <iostream>
#include <cmath>
using namespace std;

int main ()
{
	long double base = 4.4, result;
	int exponent = -3;
	result = pow(base, exponent);
	cout << base << "^" << exponent << " = " << result << endl;
	
	
	// Both arguments int
	// pow() returns double in this case
	int intBase = -4, intExponent = 6;
	double answer;
	answer = pow(intBase, intExponent);
	cout << intBase << "^" << intExponent << " = " << answer;
	
	return 0;
}

When you run the program, the output will be:

4.4^-3 = 0.0117393
-4^6 = 4096 

The abs() function in C++ returns the absolute value of the argument.

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    double x = -87.91, result;
    
    result = abs(x);
    cout << "abs(" << x << ") = |" << x << "| = " << result << endl;

    return 0;
}


























When you run the program, the output will be:

abs(-87.91) = |-87.91| = 87.91
The strlen() function in C++ returns the length of the given string.

#include <cstring>
#include <iostream>

using namespace std;

int main()
{
    char str1[] = "This a string";
    char str2[] = "This is another string";
    
    int len1 = strlen(str1);
    int len2 = strlen(str2);

    cout << "Length of str1 = " << len1 << endl;
    cout << "Length of str2 = " << len2 << endl;
    if (len1 > len2)
        cout << "str1 is longer than str2";
    else if (len1 < len2)
        cout << "str2 is longer than str1";
    else
        cout << "str1 and str2 are of equal length";

    return 0;
}



When you run the program, the output will be:
Length of str1 = 13
Length of str2 = 22
str2 is longer than str1
The toupper() function in C++ converts a given character to uppercase.

#include <cctype>
#include <iostream>
#include <cstring>
#include <cstdio>

using namespace std;

int main()
{
    char str[] = "John is from USA.";

    cout << "The uppercase version of \"" << str << "\" is " << endl;

    for (int i=0; i<strlen(str); i++)
        putchar(toupper(str[i]));
    
    return 0;
}



When you run the program, the output will be:
The uppercase version of "John is from USA." is 
JOHN IS FROM USA.


The isupper() function in C++ checks if the given character is a uppercase character or not.

#include <cctype>
#include <iostream>
#include <cstring>

using namespace std;

int main()
{
    char str[] = "This Program Converts ALL UPPERCASE Characters to LOWERCASE";

    for (int i=0; i<strlen(str); i++)
    {
        if (isupper(str[i]))
            /*  Converting uppercase characters to lowercase  */
            str[i] = str[i] + 32;
    }

    cout << str;
    return 0;
}



When you run the program, the output will be:
this program converts all uppercase characters to lowercase