Smita S.

The strlen() function in C calculates the length of a given string. The strlen() function is defined in string.h header file. It doesn’t count the null character ‘\0’.

// c program to demonstrate

// example of strlen() function.

#include <stdio.h>

#include <string.h>

int main()

{

    // defining string

    char str[] = "Hello";

    // getting length of str using strlen()

    int length = strlen(str);

    printf("Length of string is : %d", length);

    return 0;

}

You can declare an array of any data type (i.e. int, float, double, char) in C. The following ways can be used to declare and initialize an array in C. 

Array Declaration by Specifying the Size

Arrays can be declared by specifying the size or the number of array elements. The size of the array specifies the maximum number of elements that the array can hold. In the latest version of C, you can either declare an array by simply specifying the size at the time of the declaration or you can provide a user-specified size. The following syntax can be used to declare an array simply by specifying its size.

 // declare an array by specifying size in [].

int my_array1[20];

char my_array2[5];

// declare an array by specifying user defined size.

int size = 20;

int my_array3[size];

The while Loop is an entry-controlled loop in C programming language. This loop can be used to iterate a part of code while the given condition remains true.

Syntax

The while loop syntax is as follows:

while (test expression)

{

   // body consisting of multiple statements

}

struct is used to define a structure. typedef is used to give an alias name to a data type and the data type can be a predefined data type (like int,float, char) or a user defined data type. After the second declaration we will have to refer to that structure as "struct StructName" throughout the program.