Arrays C Programming Tutorial PDF

Unit 2-Array Array: Arrays a kind of data structure that can store a fixed-size sequential collection of elements of the same type. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type. Inste...

Unit 2-Array Array: Arrays a kind of data structure that can store a fixed-size sequential collection of elements of the same type. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type. Instead of declaring individual variables, such as number0, number1,..., and number99, you declare one array variable such as numbers and use numbers, numbers, and..., numbers to represent individual variables. A specific element in an array is accessed by an index. All arrays consist of contiguous memory locations. The lowest address corresponds to the first element and the highest address to the last element. Advantages of an Array in C: 1. Random access of elements using array index. 2. Use of less line of code as it creates a single array of multiple elements. 3. Easy access to all the elements. 4. Traversal through the array becomes easy using a single loop. 5. Sorting becomes easy as it can be accomplished by writing less line of code. Miss Mali Runali Page 1 Unit 2-Array Declaring Arrays: Syntax: dataType arrayName[arraySize]; Eg: float mark; It's important to note that the size and type of an array cannot be changed once it is declared. 1. Array declaration by specifying size: int arr1; int n = 10; int arr2[n]; 2. Array declaration by initializing elements: int arr[] = { 10, 20, 30, 40 } 3. Array declaration by specifying size and initializing elements: int arr = { 10, 20, 30, 40 } Miss Mali Runali Page 2 Unit 2-Array Initialization of an array: int mark[] = {19, 10, 8, 17, 9}; // print the first element of the array printf("%d", mark); // print the third element of the array printf("%d", mark); // print ith element of the array printf("%d", mark[i-1]); Miss Mali Runali Page 3 Unit 2-Array #include int main() { int i; int arr = {10,20,30,40,50}; //To initialize all array elements to 0, use int arr={0}; for (i=0;i str2 Same as strcmp() function. But, this function negotiates case. “A” strcmpi ( ) and “a” are treated as same. strchr ( ) Returns pointer to first occurrence of char in str1 strrchr ( ) last occurrence of given character in a string is found strstr ( ) Returns pointer to first occurrence of str2 in str1 strdup ( ) Duplicates the string strlwr ( ) Converts string to lowercase strupr ( ) Converts string to uppercase strrev ( ) Reverses the given string strset ( ) Sets all character in a string to given character strnset ( ) It sets the portion of characters in a string to given character strtok ( ) Tokenizing given string using delimiter Miss Mali Runali Page 8 Unit 2-Array Types of Array: Two dimensional arrays: At times we need to store the data in form of tables or matrices. For this, we can use the two dimensional arrays. Miss Mali Runali Page 9 Unit 2-Array This array is specified by using two subscripts where one subscript is denoted as the row and the other as the column. It is also viewed as an array of arrays. Above figure shows how the rows and columns are addressed in a two- dimensional array. The first subscript denotes the row and the second subscript denotes the column. i) Declaration of a two-dimensional array The declaration of the array will tell the compiler as to which array is being used for the program. Syntax: data_type array_name [row_size] [column_size] ; The declaration of the rows and columns is compulsory for a two-dimensional array. We cannot replace the row size with the column size and the column size to row size. The proper sequence has to be maintained. ii) Initialization of two-dimensional array A two-dimensional array is initialized in the same way as the one-dimensional array. Miss Mali Runali Page 10 Unit 2-Array Example: Initialization of 2D array int score ={50, 60, 70, 95, 3, 36}; The initialization of the array is done row-by-row. The above can also be written in the following manner: int score ={{50, 60} , {70,95} ,{3,36}}; The elements will be seen in the following format once they are initialized. score = 50 score = 60 score = 70 score = 95 score = 3 score = 36 The above example has been divided into three rows and two columns. iii) Accessing the elements The elements of this array are stored in a continuous memory location. The last subscript varies rapidly as compared to the first one. Two for loops required for scanning the elements of the two-dimensional array. The first for will loop for each row and second for will loop for each column for every row. Example: Simple program for printing the elements of 2D array. #include void main() Miss Mali Runali Page 11  Unit 2-Array { int score= {10,20,30,40,50,60}; int i,j; for(i=0;i