Page 46 - DCAP407_DATA_STRUCTURE

Unit 3: Arrays

Array Initialization in its Declaration
A variable is initialized in its declaration.

int value = 10;
Here, the value 10 is called an initializer.
Similar to a variable, we can initialize an array at the time of its declaration. The following example
shows an array initialization.

int a[5] = {10, 11, 12, 13, 14};

In this declaration, a[0] is initialized to 10, a[1] is initialized to 11, and so on. There must be at least one
initial value between braces. If the number of initialized array elements is lesser than the declared size,
then the remaining array elements are assigned the value 0.
If we provide all the array elements during initialization, it is not necessary to specify the array size. The
compiler automatically counts the number of elements and reserves the space in the memory for the
array.

int a[] = {10, 20, 30, 40};
Here the compiler reserves four spaces for array a.

The number of values specified during initialization cannot exceed the array size. If too
many initial values are specified, a syntax error occurs.
int weight[6] = {45, 48, 54, 58, 59, 62, 33, 21,43, 19, 4, 77};
Here, the array size is 6 but the number of initial values is 12. This leads to a syntax error.

1. While defining an array size, it is better to use a symbolic constant than specifying
a fixed quantity.
# define GVAL 30 //GVAL is the maximum size of the array which is 30
int p[GVAL]; //Declaring the array p to GVAL
2. A string consists of characters enclosed within double quotes. They are
considered as an array of characters. A string is terminated by a null character
‘\0’. String input is read using either scanf() or gets().

In a string array, a user can enter any number of characters including blank
characters. Each string is terminated by a null character.
Consider the declaration:
Char str[GVAL];

If scanf(“%s”,str) is used to read the string ‘GLOBAL WARMING’, only the string
until the blank character (space between the words) is stored and then the string
is terminated by a null character. Here, the blank character is treated as a
terminator.
The following syntax is used to read the string consisting of a blank, which acts as
a character.
scanf(“%[^\n]”,str);

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