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

Example of one dimensional array declaration:

     int marks[100];

We can store marks of 100 students in "marks" array declared above.

You can learn use of various Array concepts using C programming language by practicing following programs:

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

• C program to read values in 2-D Array.

• C program to read and display 3X3 integer Matrix using 2-D array.

• C program to check Identity Matrix.

• C program to find sum of diagonal elements of an array.

• Matrix Addition using C program.
• Matrix Subtraction using C program
• C program to print array elements in reverse order.
• 2D Array Search
• Program to delete duplicate array elements

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