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Character analysis and conversion functionsThe predefined functions in “ctype.h” library is for analyzing the character input and converting them.Analysis functionsS.NoFunctionDescription1isalpha()An alphabet or not2isdigit()A digit or not3isspace()A space, a new line or tab4ispunct()A special symbol or not5slower()A lower case letter of alphabet6isupper()An upper case letter of alphabet7isalphanumeric()An alphabet/digit or notConverting functionsFunctionDescriptiontolower()Converts an upper case alphabet to lower casetoupper()Converts a lower case alphabet to upper caseExampleLet us see a program to demonstrate character analysis and conversion functions − Live Demo#include #include void main(){ //Initializing compile time character variable// char variable = 'A'; //Reading User I/P// //printf("Enter the character : "); ... Read More
Before going to know about how to convert upper case to lower case letters without string convert function.Let us have a look on program to convert upper to lower using convert function, then you will get a clarity on what we are doing in the program −Example#include #include int main(){ char string[50]; printf("enter a string to convert to lower case"); gets(string); /reading the string printf("The string in lower case: %s", strlwr(string)); //strlwr converts all upper to lower return 0; }Outputenter a string to convert to lower case CProgramming LangUage The string ... Read More
The strlen () functionIt returns the number of characters in a string.Syntaxint strlen (string name)In this program, with the help of gets function reading the name at run time and trying to print the length of that name using strlen() function, this function returns an integer value and try to print that no using printf.Example 1 Live Demo#include #include void main(){ //Declaring string and length// char name[25]; int length; //Reading Input from user// printf("Enter your name : "); gets(name); length=strlen(name); //Printing name// printf("Your name is : "); puts(name); printf("Length of ... Read More
ProblemWhat do you mean by String to number and number to string conversion in C programming language?SolutionThere are two functions available for conversion. They are −sscanf() − convert string to numbersprintf () − used for converting number to stringString to number conversionWe can convert string to number using the sscanf() function −Syntaxsscanf (string name, “control string”, variable list)Example#include main (){ char a[20] = “02 01 2010”; int day, mon, yr; clrscr(); sscanf (a, “%d%d %d”, &day, &mon, &yr); printf ( “Day =%d”, day); printf ( “Month = %d”, mon); printf ( “Year = ... Read More
Arrays of pointers (to strings)Array of pointers is an array whose elements are pointers to the base address of the string.It is declared and initialized as follows −char *a[3 ] = {"one", "two", "three"}; //Here, a[0] is a ptr to the base add of the string "one" //a[1] is a ptr to the base add of the string "two" //a[2] is a ptr to the base add of the string "three"AdvantagesUnlink the two-dimensional array of characters. In (array of strings), in array of pointers to strings there is no fixed memory size for storage.The strings occupy as many bytes as ... Read More
Pointer is a variable which stores the address of other variable.Features of PointersFollowing are the features of pointers −Saves the memory spaceExecution time is faster because of direct access to memory location.The memory is accessed efficiently with the pointer i.e. dynamically memory is allocated and deallocated.Pointers are used with data structures.Here is an example for search demonstration −We can access and print a particular character in a string by using pointers.Following example shows how to access the elements using pointer −Example Live Demo#include int main(){ char array[5] = "Tutorial", *ptr, i, *ptr1; ptr = &array[1]; ptr1 = ptr ... Read More
ProblemWrite a C program to calculate sum and product of all elements in two-dimensional array using run time compilation.SolutionRuntime compilation or initialization is also called as dynamic allocation. Allocation of memory at the time of execution (run time) is known as dynamic memory allocation.The functions calloc() and malloc() support allocating of dynamic memory.In this program, we will calculate the sum of all elements and product of all elements of two-dimensional array at run time.Logic for computing sum of all elements in 2D array −printf("Sum array is : "); for(i=0;i
Dynamic Memory AllocationAllocation of memory at the time of execution (run time) is known as dynamic memory allocation.The functions calloc() and malloc() support allocating of dynamic memory.Dynamic allocation of memory space is done by using these functions when value is returned by functions and assigned to pointer variables.In this case, variables get allocated only if your program unit gets active.It uses the data structure called heap for implementing dynamic allocation.There is memory reusability and memory can be freed when not required.It is more efficient.In this memory allocation scheme, execution is slower than static memory allocation.Here memory can be released at ... Read More
Memory can be allocated in the following two ways −Static Memory AllocationStatic variable defines in one block of allocated space, of a fixed size. Once it is allocated, it can never be freed.Memory is allocated for the declared variable in the program.The address can be obtained by using ‘&’ operator and can be assigned to a pointer.The memory is allocated during compile time.It uses stack for maintaining the static allocation of memory.In this allocation, once the memory is allocated, the memory size cannot change.It is less efficient.The final size of a variable is decided before running the program, it will ... Read More
Pointer to functionIt holds the base address of function definition in memory.Declarationdatatype (*pointername) ();The name of the function itself specifies the base address of the function. So, initialization is done using function name.For example, int (*p) (); p = display; //display () is a function that is defined.Example 1We shall see a program for calling a function using pointer to function −#include main (){ int (*p) (); //declaring pointer to function clrscr (); p = display; *(p) (); //calling pointer to function getch (); } display (){ //called function present at pointer location printf(“Hello”); ... Read More