# Explain the concept of one and two dimensional array processing using C language

Let us first understand the one dimensional array processing in C programming language.

## 1D Array Processing

Storing values in 1 D Array(reading) is done as follows −

int num
int i;
for(i=0;i<5;i++){
Scanf("%d",&num[i]);
}

Retrieving stored values from 1D array(writing) is done as follows −

int num
int i;
for(i=0;i<5;i++){
printff("%d",num[i]);
}

## Example program

Given below is the C program to print the elements in a reverse order from an array −

Live Demo

#include<stdio.h>
void main(){
//Declaring the array - run time//
int array,i;
printf("Enter elements into the array: ");
//For loop//
for(i=0;i<5;i++){
printf("array[%d] :",i);
scanf("%d",&array[i]);
}
//Displaying reverse order of elements in the array//
printf("The elements from the array displayed in the reverse order are : ");
for(i=4;i>=0;i--){
//Displaying O/p//
printf("array[%d] :",i);
printf("%d",array[i]);
}
}

## Output

When the above program is executed, it produces the following result −

Enter elements into the array:
array :1
array :2
array :3
array :4
array :5
The elements from the array displayed in the reverse order are:
array :5
array :4
array :3
array :2
array :1

## 2D Array Processing

Storing values in 2D Array(reading) is done as follows −

int a;
int i,j;
for(i=0;i<4;i++){
for(j=0;j<3;j++){
scanf("%d",&a[i][j]);
}
}

Retrieving stored values from 2D array(writing) is done as follows −

int a;
int i,j;
for(i=0;i<4;i++){
for(j=0;j<3;j++){
printf("%d",a[i][j]);
}
}

## Example Program

Following is the C program to calculate sum and product of all elements in an array by using run time compilation −

Live Demo

#include<stdio.h>
void main(){
//Declaring the array - run time//
int A,B,i,j,sum[i][j],product[i][j];
//Reading elements into the array's A and B using for loop//
printf("Enter elements into the array A: ");
for(i=0;i<2;i++){
for(j=0;j<3;j++){
printf("A[%d][%d] :",i,j);
scanf("%d",&A[i][j]);
}
printf("");
}
for(i=0;i<2;i++){
for(j=0;j<3;j++){
printf("B[%d][%d] :",i,j);
scanf("%d",&B[i][j]);
}
printf("");
}
//Calculating sum and printing output//
printf("Sum array is : ");
for(i=0;i<2;i++){
for(j=0;j<3;j++){
sum[i][j]=A[i][j]+B[i][j];
printf("%d\t",sum[i][j]);
}
printf("");
}
//Calculating product and printing output//
printf("Product array is : ");
for(i=0;i<2;i++){
for(j=0;j<3;j++){
product[i][j]=A[i][j]*B[i][j];
printf("%d\t",product[i][j]);
}
printf("");
}
}

## Output

When the above program is executed, it produces the following result −

Enter elements into the array A:
A :2
A :3
A :4
A :1
A :2
A :3
B :4
B :5
B :3
B :2
B :1
B :2
Sum array is:
6 8 7
3 3 5
Product array is:
8 15 12
2 2 6