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C Array is a collection of variables belongings to the same data type. You can store group of data of same data type in an array.
- Array might be belonging to any of the data types
- Array size must be a constant value.
- Always, Contiguous (adjacent) memory locations are used to store array elements in memory.
- It is a best practice to initialize an array to zero or null while declaring, if we don’t assign any values to array.
Example for C Arrays:
- int a[10]; // integer array
- char b[10]; // character array i.e. string
Types of C arrays:
There are 2 types of C arrays. They are,
- One dimensional array
- Multi dimensional array
- Two dimensional array
- Three dimensional array
- four dimensional array etc…
1. One dimensional array in C:
Syntax : data-type arr_name[array_size];
Array declaration, initialization and accessing |
Example
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Array declaration syntax: data_type arr_name [arr_size];Array initialization syntax: data_type arr_name [arr_size]=(value1, value2, value3,….);Array accessing syntax: arr_name[index]; |
Integer array example:
int age [5]; age[0]; /*0 is accessed*/ Character array example: char str[10]; str[0]; /*H is accessed*/ |
Example program for one dimensional array in C:
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#include<stdio.h> int main() { int i; int arr[5] = {10,20,30,40,50}; // declaring and Initializing array in C //To initialize all array elements to 0, use int arr[5]={0}; /* Above array can be initialized as below also arr[0] = 10; arr[1] = 20; arr[2] = 30; arr[3] = 40; arr[4] = 50; */ for (i=0;i<5;i++) { // Accessing each variable printf("value of arr[%d] is %d \n", i, arr[i]); } } |
Output:
value of arr[0] is 10
value of arr[1] is 20
value of arr[2] is 30
value of arr[3] is 40
value of arr[4] is 50
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2. Two dimensional array in C:
- Two dimensional array is nothing but array of array.
- syntax : data_type array_name[num_of_rows][num_of_column];
Array declaration, initialization and accessing
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Example
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Array declaration syntax: data_type arr_name [num_of_rows][num_of_column];Array initialization syntax: data_type arr_name[2][2] = {{0,0},{0,1},{1,0},{1,1}};Array accessing syntax: arr_name[index]; |
Integer array example:
int arr[2][2]; arr [0] [0] = 1; |
Example program for two dimensional array in C:
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#include<stdio.h> int main() { int i,j; // declaring and Initializing array int arr[2][2] = {10,20,30,40}; /* Above array can be initialized as below also arr[0][0] = 10; // Initializing array arr[0][1] = 20; arr[1][0] = 30; arr[1][1] = 40; */ for (i=0;i<2;i++) { for (j=0;j<2;j++) { // Accessing variables printf("value of arr[%d] [%d] : %d\n",i,j,arr[i][j]); } } } |
OUTPUT:
value of arr[0] [0] is 10
value of arr[0] [1] is 20
value of arr[1] [0] is 30
value of arr[1] [1] is 40
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