Working with two-dimensional array at runtime in C programming

Problem

Write a C program to calculate sum and product of all elements in two-dimensional array using run time compilation.

Solution

• Runtime compilation or initialization is also called as dynamic allocation. Allocation of memory at the time of execution (run time) is known as dynamic memory allocation.

• The functions calloc() and malloc() support allocating of dynamic memory.

In this program, we will calculate the sum of all elements and product of all elements of two-dimensional array at run time.

Logic for computing sum of all elements in 2D array −

printf("Sum array is : \n");
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("\n");
}

Logic for computing product of all elements in 2D array −

printf("Product array is : \n");
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("\n");
}
}

Example

#include<stdio.h>
void main(){
   //Declaring the array - run time//
   int A[2][3],B[2][3],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: \n");
   for(i=0;i<2;i++){
      for(j=0;j<3;j++){
         printf("A[%d][%d] :",i,j);
         scanf("%d",&A[i][j]);
      }
      printf("\n");
   }
   for(i=0;i<2;i++){
      for(j=0;j<3;j++){
         printf("B[%d][%d] :",i,j);
         scanf("%d",&B[i][j]);
      }
      printf("\n");
   }
   //Calculating sum and printing output//
   printf("Sum array is : \n");
   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("\n");
   }
   //Calculating product and printing output//
   printf("Product array is : \n");
   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("\n");
   }
}

Output

Enter elements into the array A:
A[0][0] :A[0][1] :A[0][2] :
A[1][0] :A[1][1] :A[1][2] :
B[0][0] :B[0][1] :B[0][2] :
B[1][0] :B[1][1] :B[1][2] :
Sum array is :
000
000
Product array is :
000
000