Page 289 - Computer_Science_F5

Computer Science Table 4.15: Built-in function <cmath> Example
Header
Built-function
Application
<cmath>
sqrt (x)
Find the square root of x
sqrt (x)
abs (x)
Find absolute of x
abs (x)
FOR ONLINE READING ONLY
exp (x)
pow(x, y)
<cmath>
Find x power y
pow(x, y) Find the natural exponent of x <cmath> exp (x)
tolower(x) Convert character to lower case <cctype> tolower(x)
toupper(x) Convert character to upper case. <cctype> toupper(x)
Returns true if x is uppercase
isupper(x) <cctype> isupper(x)
letter, otherwise it returns false.
Returns true if x is lowercase
islower(x) <cctype> islower(x)
letter, otherwise it returns false.
isPrime Returns true if x is prime numbr, <cmath> isPrime
otherwise it returns false.

Casting
C++ uses casting technique to avoid implicit type conversion. Casting is used to
convert data type from one data type to another through the use of a cast operator.
The cast operator is also called type conversion or type casting. The following C++
Program Example 4.31 demonstrates the use of casting. The output is shown in
Figure 4.60.

Program Example 4.31:
Casting

#include<iostream>
using namespace std;
int main()
{
float l, w; //Declaration of length and width as integers data type
double area; //Declaration of area as double data type
/* This program asks you to enter length and with in float,and
displays the results in (i) float and (ii) integer
*/
cout<<”Enter a length in metres using float : “;
cin>>l; //Read value of length entered by the user
cout<<”Enter a width in metres using float: “;
cin>>w; //Read value of length entered by the user
area = l * w;
cout<<”The area of the rectangle in float (before casting) is “<<area<<” square metres”<<endl;

//use casting int(area) to get area in integer
cout<<”The area of the rectangle (after casting) is “<<int(area)<<” square metres”<<endl;
return 0;
}

280
for Advanced Secondary Schools

Computer Science Form 5.indd 280 23/07/2024 12:34