C Programming - Multidimensional Arrays, Exercises and Strings

Declaring an Multi Dimensional Array and Display the values in the array

 
      #include<stdio.h>
	int main()
	{   
		int a[2][4] = { {22,25,27,29},{33,35,38,39} };
		int i = 0, j = 0;
		for (i = 0; i < 2; i++)
		{
			for (j = 0; j < 4; j++)
			{
				printf("%d", a[i][j]);
				printf(" ");
			}
			printf("\n");
		}
		system("pause");
		return 0;
	}

Output

Addition of Two Matrices in C

 
      #include<stdio.h>
	int main()
	{   
		int a[2][2] = {0};
		int b[2][2] = { 0 };
		int result[2][2] = { 0 };
		int i = 0, j = 0;
		printf("Enter the values for matrix1\n");
		for (i = 0; i < 2; i++)
		{
			for (j = 0; j < 2; j++)
			{
				scanf("%d", &a[i][j]);
			}
		}
		printf("Enter the values for matrix 2\n");
		for (i = 0; i < 2; i++)
		{
			for (j = 0; j < 2; j++)
			{
				scanf("%d", &b[i][j]);
			}
		}
		for (i = 0; i < 2; i++)
		{
			for (j = 0; j < 2; j++)
			{
				result[i][j] = a[i][j] + b[i][j];
			}
		}
		printf("The resultant matrix is\n");
		for (i = 0; i < 2; i++)
		{
			for (j = 0; j < 2; j++)
			{
				printf("%d", result[i][j]);
				printf(" ");
			}
			printf("\n");
		}
		system("pause");
		return 0;
	}

Output

Check if a matrix is an identity matrix

 
      #include<stdio.h>
int main()
{
	int a[2][2] = { 0 };
	int i = 0, j = 0,identity=0;
	printf("Enter the values for matrix1");
	for (i = 0; i < 2; i++)
	{
		for (j = 0; j < 2; j++)
		{
			scanf("%d", &a[i][j]);
		}
	}
	for (i = 0; i < 2; i++)
	{
		for (j = 0; j < 2; j++)
		{
			if ((i == j) && (a[i][j] != 1))
			{
				identity = 1;
				printf("not an identity matrix");
				break;
			}
			if ((i != j) && (a[i][j] != 0))
			{
				identity = 1;
				printf("not an identity matrix");
				break;
			}
		}
	}
		if (identity == 0)
		{
			printf("Its an identity matrix");
		}
		system("pause");
		return 0;
	}

Output

Finding the transpose of a matrix

 
      #include<stdio.h>
int main()
{
	int a[2][2] = { 0 };
	int b[2][2] = { 0 };
	int i = 0, j = 0,identity=0;
	printf("Enter the values for matrix1");
	for (i = 0; i < 2; i++)
	{
		for (j = 0; j < 2; j++)
		{
			scanf("%d", &a[i][j]);
		}
	}
	for (i = 0; i < 2; i++)
	{
		for (j = 0; j < 2; j++)
		{
			b[i][j] = a[j][i];
		}
	}
	for (i = 0; i < 2; i++)
	{
		for (j = 0; j < 2; j++)
		{
			printf("%d", b[i][j]);
		}
	}

		system("pause");
		return 0;
	}

Output

Printing the average marks for each student

 
      #include<stdio.h>
	int main()
	{
		float a[3][5];
		int i = 0, j = 0; float sum = 0;
		float average = 0;
		for (i = 0; i < 3; i++)
		{
			for (j = 0; j < 5; j++)
			{
				scanf("%f", &a[i][j]);
			}
		}
		for (i = 0; i < 3; i++)
		{
			for (j = 0; j < 5; j++)
			{
				sum += a[i][j];
			}
			average = (float)sum / 5;
			printf("The average %d student is %f\n",i+1, average);
			sum = 0;
		}
			system("pause");
			return 0;
		}

Output

C Code for Matrix Multiplication

 
      int main()
{
    int a[10][10], b[10][10], result[10][10], r1, c1, r2, c2, i, j, k;

    printf("Enter rows and column for first matrix: ");
    scanf("%d %d", &r1, &c1);

    printf("Enter rows and column for second matrix: ");
    scanf("%d %d",&r2, &c2);

    // Column of first matrix should be equal to column of second matrix and
    while (c1 != r2)
    {
        printf("Error! column of first matrix not equal to row of second.\n\n");
        printf("Enter rows and column for first matrix: ");
        scanf("%d %d", &r1, &c1);
        printf("Enter rows and column for second matrix: ");
        scanf("%d %d",&r2, &c2);
    }

    // Storing elements of first matrix.
    printf("\nEnter elements of matrix 1:\n");
    for(i=0; i<r1; ++i)
        for(j=0; j<c1; ++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<r2; ++i)
        for(j=0; j<c2; ++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<r1; ++i)
        for(j=0; j<c2; ++j)
        {
            result[i][j] = 0;
        }

    // Multiplying matrices a and b and
    // storing result in result matrix
    for(i=0; i<r1; ++i)
        for(j=0; j<c2; ++j)
            for(k=0; k<c1; ++k)
            {
                result[i][j]+=a[i][k]*b[k][j];
            }

    // Displaying the result
    printf("\nOutput Matrix:\n");
    for(i=0; i<r1; ++i)
        for(j=0; j<c2; ++j)
        {
            printf("%d  ", result[i][j]);
            if(j == c2-1)
                printf("\n\n");
        }
    return 0;
}