Arrays

                Array provides easy way to represent our data in C program. 

If we want to store marks of 100 students, then declaring 100 different int type of variables is not a good idea in C. C language provides facility to solve this issue using concept of “Array”. An array is collection of variables with same datatype.

In C language Arrays are of two types:

• One-dimensional arrays
• Multidimensional arrays
• 
  

Syntax of Array

Array variable must be declared before its first use in C program. The general syntax of declaring one-dimensional array is as under:

data_type array_name[size_of_array];

where 

• data_type may be any valid C data type like int, char, float, etc
• array_name is valid variable name as per C language
• size_of_array indicates maximum number of elements that array can store

Sample Programs

C program to read and display 5 integer values in 1-D array.

#include<stdio.h> int main() {  int i=0, number[5];  for(i=0; i<5; i++) // This loop tracks array index   {   printf("Enter your Number[%d]:",i);   scanf("%d",&number[i]);  }  //Logic to print number array.  for(i=0; i<5; i++) // This loop tracks array index   {   printf("Number[%d]:%d \n", i, number[i]);  }  return 0; }

Output of the program:

Enter your Number[0]:2
Enter your Number[1]:4
Enter your Number[2]:6
Enter your Number[3]:8
Enter your Number[4]:10
Number[0]:2
Number[1]:4
Number[2]:6
Number[3]:8
Number[4]:10

 C program to print array elements in reverse order.

#include<stdio.h> int main() {  int i, arr1[5];  for(i=0; i<5; i++)  {   printf("Enter Element[%d]:", i);   scanf("%d",&arr1[i]);  }  printf("Array elements in reverse order are:\n");  for(i=4; i>=0; i--)  {   printf("Element[%d]: %d \n", i,arr1[i]);  } }

Output of the program:

Enter Element[0]:1

Enter Element[1]:2

Enter Element[2]:3

Enter Element[3]:4

Enter Element[4]:5

Array elements in reverse order are:

Element[4]: 5

Element[3]: 4

Element[2]: 3

Element[1]: 2

Element[0]: 1