Array in C

Array in C

• 1.
  Made By : AdityaKaushik Department : Computer Engineering (A1) Gandhinagar Institute of Technology Khatraj-Kalol Road, Gandhinagar www.git.org.in
• 2.
  What is anarray ?! An array is a collection of elements of the same type that are referenced by a common name . It is a derived data type compared to the basic data types (int , float and char) . All elements of an array occupy a set of contiguous memory locations.
• 3.
  Imagine declaring themarks of 100 students by using normal variable declaration ! Something like this : void main() int studMark; { int studMarks1, studMarks2 ,studMarks3 , studMarks4, ..., ..., studMarks99, studMarks100; ... ... return 0; }
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  By using anarray , we can just declare like this int studMark [100]; This will reserve 100 contiguous memory locations for storing student’s marks. Graphically, this can be depicted as in the following figure .
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  Array has simplifiedour declaration of the variables. We can use index or subscript to identify each element or location in the memory. For example, studMark[0] will refer to the first element of the array. Thus by changing the value of Index, we could refer to any element in the array.
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  Dimension refers tothe array's size , which is how big the array is. A single or one dimensional array declaration has the following form, array_element_data_type array_name[array_size]; Here, array_element_data_type define the base type of the array, which is the type of each element in the array. array_name is any valid C / C++ identifier name that obeys the same rule for the identifier naming.
• 7.
  Array initialization simplymeans giving initial values to an array , it must be initialized at the time of declaration. Initialization of an array may take the fllwing form, type array_name[size] = {a_list_of_value}; For example: int idNum[7] = {1, 2, 3, 4, 5, 6, 7}; float fFloatNum[5] = {5.6, 5.7, 5.8, 5.9, 6.1}; char chVowel[6] = {'a', 'e', 'i', 'o', 'u', '0'};
• 8.
  Initialization of anarray of type char for holding strings may take the following form, char array_name[size] = "string_lateral_constant"; For example, the array chVowel in the previous example could have been written more compactly as follows, char chVowel[6] = "aeiou"; When the value assigned to a character array is a string (which must be enclosed in double quotes), the compiler automatically supplies the NULL character but we still have to reserve one extra place for the NULL. C compiler automatically creates an array which is big enough to hold all the initializer.
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  Arrays allow programmersto group related items of the same data type in one variable. However, when referring to an array, one has to specify not only the array or variable name but also the index number of interest. Program example 1: Sum of array’s element. Notice the array's element which is not initialized is set to 0 automatically.
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  A two dimensionalarray has two subscripts/indexes. The first subscript refers to the row, and the second, to the column. Its declaration has the following form, data_type array_name[1st dimension size][2nd dimension size]; For examples, int xInteger[3][4]; float matrixNum[20][25];
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  If we assigninitial string values for the 2D array it will look something like the following, char Name[6][10] = {"Mr. Bean", "Mr. Bush", "Nicole", "Kidman", "Arnold", "Jodie"}; Here, we can initialize the array with 6 strings, each with maximum 9 characters long. It would look something like this.
• 12.
  Take note thatfor strings the null character (0) still needed. The array size is = First index * second index = xy. This stands true for all dimensions of array . for e.g. 3-Dimensional array; array_name[x][y][z]; First index * second index * third index = xyz
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  The contents ofthe array in memory after the three strings are read in the array. Re-run the program, enter the following data: “you”, “my”. Illustrates the content as done previously.
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  The End. 