6-1 (Function). (Function) !*+!"#!, Function Description Example. natural logarithm of x (base e) rounds x to smallest integer not less than x

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1 (Function) -1.1 Math Library Function!"#! $%&!'(#) preprocessor directive #include <math.h>!*+!"#!, Function Description Example sqrt(x) square root of x sqrt(900.0) is 30.0 sqrt(9.0) is 3.0 exp(x) log(x) log10(x) fabs(x) ceil(x) floor(x) pow(x,y) fmod(x,y) sin(x) cos(x) tan(x) exponential function e x natural logarithm of x (base e) logarithm of x (base 10) absolute value of x rounds x to smallest integer not less than x rounds x to largest integer not greater than x x raised to power y(x y ) remainder of x/y as a floating point number trigonometric sine of x (x is trigonometric cosine of x (x is trigonometric tangent of x (x is exp(1.0) is exp(2.0) is log( ) is 1.0 log( ) is 2.0 log10(1.0) is 0.0 log10(10.0) is 1.0 log10(100.0) is 2.0 fabs(5.0) is 5.0 fabs(0.0) is 0.0 fabs(-5.0) is 5.0 ceil(9.2) is 10.0 ceil(-9.8) is -9.0 floor(9.2) is 9.0 floor(-9.8) is pow(2, 7) is pow(9,.5) is 3.0 fmod(13.57, 2.333) is sin(0.0) is 0.0 cos(0.0) is 1.0 tan(0.0) is 0.0 1

2 -1.2 Header -!./0)$%&123/4 header -5) )12 3/ -!.4$%&12!'(#include <file.h> 3#-!*+ Standard libray header <float.h> <math.h> <stdio.h> <stdlib.h> <string.h> <time.h>!*+standard library header Explanation Contains the floating point size limits of the system. Contains function prototypes for math library Contains function prototypes for the standard input/output library functions, and information used by them. Contains function prototypes for conversions of numbers to text and text to numbers, memory allocation, random numbers, and other utility Contains function prototypes for string processing Contains function prototypes and types for manipulating the time and date #-812#, header 3, 05#include file.h -5!!)2()#include <file.h> 52 #include file.h + #include <file.h> 39(0) 12'-39 -!.-$%& + 8'(#include file.h preprocessor directive 12(, 12'34-3/1directory 3/, '12-,: -1.3 Random Number Generation #)-3;)1'3!<-2() 52 =>?@AB>C D39) '(EFGHIJ+KLKMNGMOP 1 /* Program: exam-1_1.c 2 Objective: To Shifted, scaled integers produced by rand() % 4 */ 5 #include <stdio.h> #include <stdlib.h> 7 8 int main() 9 { 10 int i; /*counter */ 11 for (i=1; i<=20; i++){ /* loop 20 times */ 2

3 12 /* pick random number from 1 to and output it */ 13 printf( %10d, 1 + (rand()%)); 15 /* if counter is divisible by 5, begin new line 1 of output */ 17 if (i%5 == 0) 18 printf( \n ); 19 } /* end for */ return 0; /*indicates successful termination */ 22 } /* end main */ 1 /* Program: exam-1_2.c 2 Objective: To Roll a six-sided die 000 times 3 */ 4 #include <stdio.h> 5 #include <stdlib.h> 9 int frequency1 = 0; /* rolled 1 counter */ 10 int frequency2 = 0; /* rolled 2 counter */ 11 int frequency3 = 0; /* rolled 3 counter */ 12 int frequency4 = 0; /* rolled 4 counter */ 13 int frequency5 = 0; /* rolled 5 counter */ int frequency = 0; /* rolled counter */ 15 1 int roll; /* roll counter, value 1 to 000 */ 17 int face; /* represents one roll of the die, 18 value 1 to */ /* loop 000 times and summarize results */ 21 for (roll=1; roll <= 000; roll++){ 22 face = 1+rand()%; /*random number from 1 to */ switch (face){ 25 case 1: /*rolled 1 */ 2 ++frequency1; 27 break; 28 case 2: /*rolled 2 */ 29 ++frequency2; 30 break; 31 case 3: /*rolled 3 */ 32 ++frequency3; 33 break; 34 case 4: /*rolled 4 */ 35 ++frequency4; 3 break; 37 case 5: /*rolled 5 */ 38 ++frequency5; 39 break; 40 case : /*rolled */ 41 ++frequency; 3

4 42 break; 43 } /* end switch */ 44 } /* end for */ 45 /* display results in tabular format */ 4 printf( %s%13s\n, Face, Frequency ); 47 printf( 1%13d\n, frequency1); 48 printf( 2%13d\n, frequency2); 49 printf( 3%13d\n, frequency3); 50 printf( 4%13d\n, frequency4); 51 printf( 5%13d\n, frequency5); 52 printf( %13d\n, frequency); return 0; 55 5 } /* end main */ 39 12'(3341'3!<-5#)-3/- DQEMRGSONTGSU TRUJMOEP3/ 12'(3'41'V4W/)#)-/),<!- 12'(3'3&'5!)275-' &W83!!1#' !('#)-341'3!<-5!!),3/ (75-' 1W! &W 12'()1'3!<- DRTEIXTMG ITFMXMOP 52 3:; 12(,'41'3!<-#)-5!!) 'DQOSXONUMYMZRFISTP 1 /* Program: exam-1_3.c 2 Objective: Randomizing die-rolling program 3 */ 4 #include <stdlib.h> 5 #include <stdio.h> 9 int i; /*counter */ 10 unsigned seed; /* number used to seed random number 11 generator */ 12 printf( Enter seed: ); 13 scanf( %u, &seed); /* %u for unsigned*/ 15 srand(seed); /*seed random number generator */ 1 /* loop 10 times */ 17 for (i=1; i<=10; i++){ 18 /* pick a random number from 1 to and output it */ 19 printf( %10d, 1+(rand()%)); if (i%5 == 0) 22 printf( \n ); 23 }/*end for */ 4

5 24 25 return 0; 2 27 } /*end main */ -1.4 Recursion 3 &(recursive function) ; 3/!37/!52-[) ;!/)4!"#! 39 3 &,5)n!, Fibonacci!n! = n (n-1)(n-2) 1 7/! = 1 1 /* Program: exam-1_4.c 2 Objective: Show how to write recursive factorial function 3 4 #include <stdio.h> 5 long factorial (long number); /* function prototype */ 9 int i; /* counter */ 10 const int n = 10; for (i=0; i<=n; i++) 13 printf( %2d! = %ld\n, I, factorial(i)); 15 return 0; 1 } /* end main */ long factorial(long number) 19 { 20 if (number <= 1) 21 return 1; 22 else 23 return(number * factorial(number-1)); 24 } /*end function factorial */ 5

C Functions. 5.2 Program Modules in C

C Functions. 5.2 Program Modules in C 1 5 C Functions 5.2 Program Modules in C 2 Functions Modules in C Programs combine user-defined functions with library functions - C standard library has a wide variety of functions Function calls Invoking