1. Mathematical Functions
CSC 215
Mathematical Functions

2. math.h Include mathematical functions
All functions in this library take double as an argument
All functions in this library return double as the result.

3. double sqrt(double x) Parameter: x − This is the floating point value.
Return Value: Returns the square root of x.
Example:
#include <stdio.h>
#include <math.h>
int main () {
printf("Square root of %lf is %lf\n", 16.0, sqrt(16.0) );
return(0); }
Output: Square root of is

4. double pow (double x, double y)
Parameters
x − This is the floating point base value.
y − This is the floating point power value.
Return Value:
This function returns the result of raising x to the power y.
Example:
#include <stdio.h>
#include <math.h>
int main () {
printf("Value 2.0 ^ 3 = %lf\n", pow(2.0, 3));
return(0); }
Output: Value 2.0 ^ 3 =

5. double fabs(double x) Output:
Parameters
x − This is the floating point value.
Return Value
This function returns the absolute value of x.
Example:
#include <stdio.h>
#include <math.h>
int main () {
int a, b;
a = 1234;
b = -344;
double c = -135;
printf("The absolute value of %d is %lf\n", a, fabs(a));
printf("The absolute value of %d is %lf\n", b, fabs(b));
printf("The absolute value of %lf is %lf\n", c, fabs(c));
return(0); }
Output:
The absolute value of 1234 is
The absolute value of -344 is
The absolute value of is

6. double ceil (double x) Output: value1 = 2.0 value2 = 2.0 value3 = 3.0
Parameters
x − This is the floating point value.
Return Value
This function returns the smallest integral value not less than x.
Example:
#include <stdio.h>
#include <math.h>
int main () {
float val1=1.6, val2=1.2, val3=2.8;
int val4 = 2;
printf ("value1 = %.1lf\n", ceil(val1));
printf ("value2 = %.1lf\n", ceil(val2));
printf ("value3 = %.1lf\n", ceil(val3));
printf ("value4 = %.1lf\n", ceil(val4));
return(0); }
Output:
value1 = 2.0
value2 = 2.0
value3 = 3.0
value4 = 2.0

7. double floor (double x)
Parameters
x − This is the floating point value.
Return Value
This function returns the largest integral value not greater than x.
Example:
#include <stdio.h>
#include <math.h>
int main () {
float val1 = 1.6, val2 = -9.8, val3 = 2.8;
int val4 = 2;
printf("Value1 = %.1lf\n", floor(val1));
printf("Value2 = %.1lf\n", floor(val2));
printf("Value3 = %.1lf\n", floor(val3));
printf("Value4 = %.1lf\n", floor(val4));
return(0); }
Output:
Value1 = 1.0
Value2 = -10.0
Value3 = 2.0
Value4 = 2.0

8. double fmod(double x, double y)
Parameters
x − This is the floating point value with the division numerator i.e. x.
y − This is the floating point value with the division denominator i.e. y
.Return Value
This function returns the remainder of dividing x/y.
Example:
#include <stdio.h>
#include <math.h>
int main () {
float a = 9.2;
float b = 3.2;
int c = 2;
printf("Remainder of %f / %d is %lf\n", a, c, fmod(a,c));
printf("Remainder of %f / %f is %lf\n", a, b, fmod(a,b));
return(0); }
Output:
Remainder of / 2 is
Remainder of / is

9. double log10(double x) Output: log10(10000.000000) = 4.000000
Parameters
x − This is the floating point value.
.Return Value
This function returns the common logarithm of x, for values of x greater than zero
Example:
#include <stdio.h>
#include <math.h>
int main ()
{double x, ret;
x = 10000;
/* finding value of log */
ret = log10(x);
printf("log10(%lf) = %lf\n", x, ret);
return(0); }
Output:
log10( ) =

10. Random Number Generation
The function rand() computes a sequence of pseudo-random integers in the range zero to RAND_MAX, which is defined in <stdlib.h>.
RAND_MAX is a constant whose default value may vary between implementations but it is granted to be at least
int rand(void)
Return Value:
This function returns an integer value between 0 and RAND_MAX.

11. Example:
#include <stdio.h> #include <stdlib.h> int main() { int i, n = 5; /* Print 5 random numbers from 0 to 49 */ for( i = 0 ; i < n ; i++ ) printf("%d\n", rand() % 50); } return(0);
Output: 33 36 27 15 43