Calculate the Sum of the Elements of each Row & Column In Matrix

#include <stdio.h>
int Addrow(int array1[10][10], int k, int c);
int Addcol(int array1[10][10], int k, int r);

void main()
{
    int arr[10][10];
    int i, j, row, col, rowsum, colsum, sumall=0;

    printf("Enter the order of the matrix \n");
    scanf("%d %d", &row, &col);
    printf("Enter the elements of the matrix \n");
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
            scanf("%d", &arr[i][j]);
        }
    }
    printf("Input matrix is \n");
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < col; j++)
        {
            printf("%3d", arr[i][j]);
        }
        printf("\n");
    }
    /*  computing row sum */
    for (i = 0; i < row; i++)
    {
        rowsum = Addrow(arr, i, col);
        printf("Sum of row %d = %d\n", i + 1, rowsum);
    }
    /*  computing col sum */
    for (j = 0; j < col; j++)
    {
        colsum = Addcol(arr, j, row);
        printf("Sum of column  %d = %d\n", j + 1, colsum);
    }
    /*  computation of all elements */
    for (j = 0; j < row; j++)
    {
        sumall = sumall + Addrow(arr, j, col);
    }
    printf("Sum of all elements of matrix = %d\n", sumall);
}
/*  Function to add each row */
int Addrow(int array1[10][10], int k, int c)
{
    int rsum = 0, i;
    for (i = 0; i < c; i++)
    {
        rsum = rsum + array1[k][i];
    }
    return(rsum);
}
/*  Function to add each column */
int Addcol(int array1[10][10], int k, int r)
{
    int csum = 0, j;
    for (j = 0; j < r; j++)
    {
        csum = csum + array1[j][k];
    }
    return(csum);
}

Interchange any two Rows & Columns in the given Matrix

#include <stdio.h>

 

void main()

{

    static int array1[10][10], array2[10][10];

    int i, j, m, n, a, b, c, p, q, r;

 

    printf("Enter the order of the matrix \n");

    scanf("%d %d", &m, &n);

    printf("Enter the co-efficents of the matrix \n");

    for (i = 0; i < m; ++i)

    {

        for (j = 0; j < n; ++j)

        {

            scanf("%d,", &array1[i][j]);

            array2[i][j] = array1[i][j];

        }

    }

    printf("Enter the numbers of two rows to be exchanged \n");

    scanf("%d %d", &a, &b);

    for (i = 0; i < m; ++i)

    {

        /*  first row has index is 0 */

        c = array1[a - 1][i];

        array1[a - 1][i] = array1[b - 1][i];

        array1[b - 1][i] = c;

    }

    printf("Enter the numbers of two columns to be exchanged \n");

    scanf("%d %d", &p, &q);

    printf("The given matrix is \n");

    for (i = 0; i < m; ++i)

    {

        for (j = 0; j < n; ++j)

            printf(" %d", array2[i][j]);

        printf("\n");

    }

    for (i = 0; i < n; ++i)

    {

        /*  first column index is 0 */

        r = array2[i][p - 1];

        array2[i][p - 1] = array2[i][q - 1];

        array2[i][q - 1] = r;

     }

    printf("The matix after interchanging the two rows(in the original matrix) \n");

    for (i = 0; i < m; ++i)

    {

        for (j = 0; j < n; ++j)

        {

            printf(" %d", array1[i][j]);

        }

        printf("\n");

     }

    printf("The matix after interchanging the two columns(in the original matrix) \n");

    for (i = 0; i < m; ++i)

    {

        for (j = 0; j < n; ++j)

            printf(" %d", array2[i][j]);

        printf("\n");

    }

}

Check if a given Matrix is an Identity Matrix

#include <stdio.h>

void main()
{
    int a[10][10];
    int i, j, row, column, flag = 1;

    printf("Enter the order of the matrix A \n");
    scanf("%d %d", &row, &column);
    printf("Enter the elements of matrix A \n");
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < column; j++)
        {
            scanf("%d", &a[i][j]);
        }
    }
    printf("MATRIX A is \n");
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < column; j++)
        {
            printf("%3d", a[i][j]);
        }
        printf("\n");
    }
    /*  Check for unit (or identity) matrix */
    for (i = 0; i < row; i++)
    {
        for (j = 0; j < column; j++)
        {
            if (a[i][j] != 1 && a[j][i] != 0)
            {
                flag = 0;
                break;
            }
        }
    }
    if (flag == 1 )
        printf("It is identity matrix \n");
    else
        printf("It is not a identity matrix \n");
}

Check whether a given Character is present in a String, Find Frequency & Position of Occurrence

#include <stdio.h>
#include <string.h>

int main()
{
    char a, word[50];
    int i, freq = 0, flag = 0;

    printf("Enter character: ");
    scanf("%c", &a);
    printf("Now enter the word: ");
    scanf("%s", word);
    printf("Positions of '%c' in %s are: ", a, word);
    for (i = 0; i < strlen(word); i++)
    {
        if (word[i] == a)
        {
            flag = 1;
            printf("%d  ", i + 1);
            freq++;
        }
    }
    if (flag)
    {
        printf("\nCharacter '%c' occured for %d times.\n", a, freq);
    }
    else
    {
        printf("None\n");
    }

    return 0;
}

Accepts two Strings & Compare them

#include <stdio.h>

void main()
{
    int count1 = 0, count2 = 0, flag = 0, i;
    char string1[10], string2[10];

    printf("Enter a string:");
    gets(string1);
    printf("Enter another string:");
    gets(string2);
    /*  Count the number of characters in string1 */
    while (string1[count1] != '\0')
        count1++;
    /*  Count the number of characters in string2 */
    while (string2[count2] != '\0')
        count2++;
    i = 0;

    while ((i < count1) && (i < count2))
    {
        if (string1[i] == string2[i])
        {
            i++;
            continue;
        }
        if (string1[i] < string2[i])
        {
            flag = -1;
            break;
        }
        if (string1[i] > string2[i])
        {
            flag = 1;
            break;
        }
    }
    if (flag == 0)
        printf("Both strings are equal \n");
    if (flag == 1)
        printf("String1 is greater than string2 \n", string1, string2);
    if (flag == -1)
        printf("String1 is less than string2 \n", string1, string2);
}

Printing Random Numbers

#include <stdio.h>#include <stdlib.h> int main() {  int c, n;   printf("Ten random numbers in [1,100]\n");   for (c = 1; c <= 10; c++) {    n = rand() % 100 + 1;    printf("%d\n", n);  }   return 0;}

Counting Frequency of character

#include <stdio.h>
#include <string.h>

int main()
{
   char string[100];
   int c = 0, count[26] = {0};

   printf("Enter a string\n");
   gets(string);

   while (string[c] != '\0')
   {
     

      if (string[c] >= 'a' && string[c] <= 'z') 
         count[string[c]-'a']++;

      c++;
   }

   for (c = 0; c < 26; c++)
   {
      

      if (count[c] != 0)
         printf("%c occurs %d times in the entered string.\n",c+'a',count[c]);
   }

   return 0;
}