Category Archives: C

Question: What are Various Trigonometric Functions in Standard C Library? Answer: Following trigonometric functions are defined in ‘math.h’ header. double sin(double angle); double cos(double angle); double tan(double angle); double asin(double angle); double acos(double angle); double atan(double angle); double atan2(double x, double y); Recall that PI radians equals 180 degrees. Functions ‘sin()’, ‘cos()’ and ‘tan()’ take … Read more

Question: What are Different Floating-Point Functions in Standard C Library? Answer: Most of the floating-point functions defined in ‘math.h’ header take their arguments as double and return double values. These functions range from Trigonometric to Hyperbolic to Logarithmic and Exponential to Power functions to Floor, Ceiling, Absolute value and Remainder functions to String conversion functions. … Read more

Question: Which String Conversion Functions in Standard C Library Return Type “double” Values? Answer: Following two functions take string as arguments and convert them into double values. double atof(char const *string); double strtod(char const *string, char **ptr2loc); These are defined in ‘stdlib.h’ header. Notice that if second argument to ‘strtod()’ function is not NULL then … Read more

Question: What are Different String Conversion Functions in Standard C Library? Answer: We have following functions which take character string with valid integers as first argument and return integer and long integer respectively as function value. These perform base 10 conversions. int atoi(char const *string); long int atol(char const *string); Function given below long int … Read more

Question: What are Random and Pseudo-Random Numbers and how are they Used in a C Program? Answer: GNU provides facilities for generating ‘pseudo-random numbers’. These aren’t truly random; sequence of numbers generated repeats periodically, though, over a large period so that we generally ignore this. Where, actually, we need to use such numbers implies situations, … Read more

Question: What are Various Integer Functions in Standard C Library? Answer: This group of functions return integer values. These functions comprise three categories viz. arithmetic, random numbers and string conversion functions. Arithmetic group of functions are prototyped below int abs(int value); long int labs(long int value); div_t div(int numerator, int denominator); div_t ldiv(long int numerator, … Read more

Question: What is Standard Library and How this Empowers a C Programmer Answer: Programming in C requires any C program to use various different functions for different requirements to be best taken care of. For ex. to copy a string ‘strcpy()’ library function, for printing formatted data to stdout, ‘printf()’ is used. There are several … Read more