Multiply Matrix and Multidimensional Array Operation

Key Architecture Takeaways

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  Point 1: Core computer science and engineering computing concept: Multiply Matrix and Multidimensional Array Operation.
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  Point 2: Detailed trace of memory representation, algorithmic complexity, and control structures.
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  Point 3: Includes portable ISO C (C17/C23) code examples verified with modern GCC and Clang.

> gcc -Wall -Wextra -O2 program.c -o program
> ./program
> ```


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[We have seen our previous post how to declare multidimensional arrays](https://www.technhit.in/using-arrays-c-language-example/). Here we play with multidimensional arrays  like Sum of Matrix, Multiply of Matrix etc. [We have already programmed sum and average of single dimension array in ](https://www.technhit.in/c-program-sum-average-array/)ours previous post. As we discuss earlier, more than 3 dimension arrays are difficult to imagine as well as implementation and execution. That's why we first use two dimension array as for example.

## C Program to store values into two-dimensional array:

c // C program to store marks of 3 year Semester and display it. #include <stdio.h>

int main() { int YEAR = 3; int SEM = 2; int marks[3][2]; int i,j; clrscr(); for (i = 0; i < YEAR; ++i) { for(j = 0; j < SEM; ++j) { printf("Year %d, Semester %d: ", i+1, j+1); scanf("%d", &marks[i][j]); } }

printf("\nDisplaying values: \n\n"); for ( i = 0; i < YEAR; ++i) { for( j = 0; j < SEM; ++j) { printf(" You have enter %d Year, %d Semester marks = %d\n", i+1, j+1, marks[i][j]); } } getch(); return 0; }

Output:

[![Multiply Matrix](https://www.technhit.in/wp-content/uploads/2016/10/storing-value.png)](https://www.technhit.in/wp-content/uploads/2016/10/storing-value.png)

## C Program to Calculate sum of 2x2 Matrix:

c #include <stdio.h> int main() { float a[2][2], b[2][2], c[2][2]; int i, j;

// Storing Values into matrix a using nested for loop clrscr(); printf("Enter elements of 1st matrix\n"); for(i=0; i<2; ++i) for(j=0; j<2; ++j) { printf("Enter a%d%d: ", i+1, j+1); scanf("%f", &a[i][j]); }

// Storing Values into matrix b using nested for loop printf("Enter elements of 2nd matrix\n"); for(i=0; i<2; ++i) for(j=0; j<2; ++j) { printf("Enter b%d%d: ", i+1, j+1); scanf("%f", &b[i][j]); }

// adding corresponding elements of two arrays into third array c for(i=0; i<2; ++i) for(j=0; j<2; ++j) { c[i][j] = a[i][j] + b[i][j]; }

// Displaying the sum printf("\nSum Of Matrix:\n");

for(i=0; i<2; ++i) for(j=0; j<2; ++j) { printf("%.1f\t", c[i][j]); if(j==1) printf("\n"); } getch(); return 0; }

Output:

[![sum](https://www.technhit.in/wp-content/uploads/2016/10/sum.png)](https://www.technhit.in/wp-content/uploads/2016/10/sum.png)

## C Program to Calculate Multiplay of 2x2 Matrix:

An *n* x *m* matrix **A** and *m* x *p* matrix **B** can be multiplied together giving a *n* x *p* matrix **C**. It is important that the first matrix (**A**) has the same number of columns as the second (**B**) has rows.

[To know more details click here](http://l4labs.soton.ac.uk/tutorials/maths/matrices.htm)

c #include <stdio.h>

int main() { int a[2][2], b[2][2], result[2][2], i, j, k;

// Storing elements of first matrix. printf("\nEnter elements of matrix 1:\n"); for(i=0; i<2; ++i) for(j=0; j<2; ++j) { printf("Enter elements a%d%d: ",i+1, j+1); scanf("%d", &a[i][j]); }

// Storing elements of second matrix. printf("\nEnter elements of matrix 2:\n"); for(i=0; i<2; ++i) for(j=0; j<2; ++j) { printf("Enter elements b%d%d: ",i+1, j+1); scanf("%d",&b[i][j]); }

// Initializing all elements of result matrix to 0 for(i=0; i<2; ++i) for(j=0; j<2; ++j) { result[i][j] = 0; }

// Multiplying matrices a and b and // storing result in result matrix for(i=0; i<2; ++i) for(j=0; j<2; ++j) for(k=0; k<2; ++k) { result[i][j]+=a[i][k]*b[k][j]; }

// Displaying the result printf("\nOutput Matrix:\n"); for(i=0; i<2; ++i) for(j=0; j<2; ++j) { printf("%d ", result[i][j]); if(j == 2-1) printf("\n\n"); } return 0; } ```

Output:

multiply