matrix multiplication in c

1double[][] c = new double[N][N];
2for (int i = 0; i < N; i++)
3{
4 for (int j = 0; j < N; j++)
5 	{
6 for (int k = 0; k < N; k++)
7 		{
8		 c[i][j] += a[i][k] * b[k][j];
9 		}
10 	}
11}
12

1#include <stdio.h>
2
3void main ()
4{
5    int i, j, k, m1, n1, m2, n2;
6    int matrix1[10][10],matrix2[10][10],mult[10][10];
7
8    printf("Enter number of rows of matrix 1 : ");
9    scanf("%d", &m1);
10    printf("Enter number of columns of matrix 1 : ");
11    scanf("%d", &n1);
12
13    printf("\n");
14
15    for (i = 0; i < m1; i++)
16    {
17        for (j = 0; j < n1; j++)
18        {
19            printf("Enter element of matrix 1[%d][%d]: ", i, j);
20            scanf("%d", &matrix1[i][j]);
21        }
22    }
23
24    printf("\n");
25
26    printf("Enter number of rows of matrix 2 : ");
27    scanf("%d", &m2);
28    printf("Enter number of columns of matrix 2 : ");
29    scanf("%d", &n2);
30
31    printf("\n");
32
33    if(m1==n2)
34    {
35        for (i = 0; i < m2; i++)
36        {
37            for (j = 0; j < n2; j++)
38            {
39                printf("Enter elements of matrix 2[%d][%d]: ", i, j);
40                scanf("%d", &matrix2[i][j]);
41            }
42        }
43
44        printf("\n");
45
46        printf("\n....Your resultant matrix is....\n\n");
47
48       for(i=0;i<m1;i++)
49        {
50            for(j=0;j<n2;j++)
51            {
52                mult[i][j]=0;
53                for(k=0;k<m2;k++)
54                {
55                    mult[i][j]+=matrix1[i][k]*matrix2[k][j];
56                }
57            }
58        }
59
60        for (i = 0; i < m1; i++)
61        {
62            for (j = 0; j < n2; j++)
63            {
64                printf("%d\t", mult[i][j]);
65            }
66            printf("\n");
67        }
68
69    }
70
71    else
72        printf("Matrix multiplication not possible");
73}
74
75
76

1#include <stdio.h>
2
3// function to get matrix elements entered by the user
4void getMatrixElements(int matrix[][10], int row, int column) {
5
6   printf("\nEnter elements: \n");
7
8   for (int i = 0; i < row; ++i) {
9      for (int j = 0; j < column; ++j) {
10         printf("Enter a%d%d: ", i + 1, j + 1);
11         scanf("%d", &matrix[i][j]);
12      }
13   }
14}
15
16// function to multiply two matrices
17void multiplyMatrices(int first[][10],
18                      int second[][10],
19                      int result[][10],
20                      int r1, int c1, int r2, int c2) {
21
22   // Initializing elements of matrix mult to 0.
23   for (int i = 0; i < r1; ++i) {
24      for (int j = 0; j < c2; ++j) {
25         result[i][j] = 0;
26      }
27   }
28
29   // Multiplying first and second matrices and storing it in result
30   for (int i = 0; i < r1; ++i) {
31      for (int j = 0; j < c2; ++j) {
32         for (int k = 0; k < c1; ++k) {
33            result[i][j] += first[i][k] * second[k][j];
34         }
35      }
36   }
37}
38
39// function to display the matrix
40void display(int result[][10], int row, int column) {
41
42   printf("\nOutput Matrix:\n");
43   for (int i = 0; i < row; ++i) {
44      for (int j = 0; j < column; ++j) {
45         printf("%d  ", result[i][j]);
46         if (j == column - 1)
47            printf("\n");
48      }
49   }
50}
51
52int main() {
53   int first[10][10], second[10][10], result[10][10], r1, c1, r2, c2;
54   printf("Enter rows and column for the first matrix: ");
55   scanf("%d %d", &r1, &c1);
56   printf("Enter rows and column for the second matrix: ");
57   scanf("%d %d", &r2, &c2);
58
59   // Taking input until
60   // 1st matrix columns is not equal to 2nd matrix row
61   while (c1 != r2) {
62      printf("Error! Enter rows and columns again.\n");
63      printf("Enter rows and columns for the first matrix: ");
64      scanf("%d%d", &r1, &c1);
65      printf("Enter rows and columns for the second matrix: ");
66      scanf("%d%d", &r2, &c2);
67   }
68
69   // get elements of the first matrix
70   getMatrixElements(first, r1, c1);
71
72   // get elements of the second matrix
73   getMatrixElements(second, r2, c2);
74
75   // multiply two matrices.
76   multiplyMatrices(first, second, result, r1, c1, r2, c2);
77
78   // display the result
79   display(result, r1, c2);
80
81   return 0;
82}

1#include <stdio.h>
2
3int main()
4{   int a_rows,a_cols,b_rows,b_cols,i,j,k,sum=0;
5
6    printf("Enter the rows and columns for first matrix (row)(col)  :\n");
7    scanf("%d %d",&a_rows,&a_cols);
8
9    printf("Enter the rows and columns for second matrix (row)(col) :\n");
10    scanf("%d %d",&b_rows,&b_cols);
11    int a[a_rows][a_cols], b[b_rows][b_cols],matrix[10][10];
12
13    if(a_cols != b_rows){
14        printf("Sorry! We can't multiply the matrix because the column number of matrix 1 and the row number of matrix 2 aren't same !!\n");
15        
16    }else{
17        printf("Enter elements for first matrix  :\n");
18       for(i = 0; i < a_rows; i++){
19           for(j = 0; j< a_cols; j++){
20               scanf("%d",&a[i][j]);
21           }
22       }
23
24    printf("Enter elements for second matrix  :\n");
25
26       for(i = 0; i < b_rows; i++){
27           for(j = 0; j < b_cols; j++){
28               scanf("%d",&b[i][j]);
29           }
30       }
31
32       printf("multiplying matrix....\n");
33       //multiplying matrix
34       for(i=0; i < a_rows; i++){
35           for(j = 0; j < b_cols; j++){
36               for(k = 0; k < a_cols; k++){
37                   sum+=a[i][k] * b[k][j];
38               }
39               matrix[i][j] = sum;
40               sum=0;
41               
42           }
43           printf("\n");
44       }
45
46       printf("first matrix  :\n");
47       for(i = 0; i < a_rows; i++){
48           for(j = 0; j< a_cols; j++){
49               printf("%d ",a[i][j]);
50           }
51           printf("\n");
52       }
53
54
55        printf("\n\n");
56
57       printf("second matrix  :\n");
58       for(i = 0; i < b_rows; i++){
59           for(j = 0; j< b_cols; j++){
60               printf("%d ",b[i][j]);
61           }
62           printf("\n");
63       }
64
65
66       printf("Multiplied matrix  :\n");
67       for(i = 0; i < a_rows; i++){
68           for(j = 0; j< b_cols; j++){
69               printf("%d ",matrix[i][j]);
70           }
71           printf("\n");
72       }
73    }
74
75     
76
77    return 0;
78}

1#include <stdio.h>
2void enterData(int first[][10], int second[][10], int r1, int c1, int r2, int c2);
3void multiplyMatrices(int first[][10], int second[][10], int multResult[][10], int r1, int c1, int r2, int c2);
4void display(int mult[][10], int r1, int c2);
5
6int main() {
7    int first[10][10], second[10][10], mult[10][10], r1, c1, r2, c2;
8    printf("Enter rows and column for the first matrix: ");
9    scanf("%d %d", &r1, &c1);
10    printf("Enter rows and column for the second matrix: ");
11    scanf("%d %d", &r2, &c2);
12
13    // Taking input until columns of the first matrix is equal to the rows of the second matrix
14    while (c1 != r2) {
15        printf("Error! Enter rows and columns again.\n");
16        printf("Enter rows and columns for the first matrix: ");
17        scanf("%d%d", &r1, &c1);
18        printf("Enter rows and columns for the second matrix: ");
19        scanf("%d%d", &r2, &c2);
20    }
21
22    // Function to take matrices data
23    enterData(first, second, r1, c1, r2, c2);
24
25    // Function to multiply two matrices.
26    multiplyMatrices(first, second, mult, r1, c1, r2, c2);
27
28    // Function to display resultant matrix after multiplication.
29    display(mult, r1, c2);
30
31    return 0;
32}
33
34void enterData(int first[][10], int second[][10], int r1, int c1, int r2, int c2) {
35    printf("\nEnter elements of matrix 1:\n");
36
37    for (int i = 0; i < r1; ++i) {
38        for (int j = 0; j < c1; ++j) {
39            printf("Enter a%d%d: ", i + 1, j + 1);
40            scanf("%d", &first[i][j]);
41        }
42    }
43    printf("\nEnter elements of matrix 2:\n");
44
45    for (int i = 0; i < r2; ++i) {
46        for (int j = 0; j < c2; ++j) {
47            printf("Enter b%d%d: ", i + 1, j + 1);
48            scanf("%d", &second[i][j]);
49        }
50    }
51}
52
53void multiplyMatrices(int first[][10], int second[][10], int mult[][10], int r1, int c1, int r2, int c2) {
54
55    // Initializing elements of matrix mult to 0.
56    for (int i = 0; i < r1; ++i) {
57        for (int j = 0; j < c2; ++j) {
58            mult[i][j] = 0;
59        }
60    }
61
62    // Multiplying first and second matrices and storing in mult.
63    for (int i = 0; i < r1; ++i) {
64        for (int j = 0; j < c2; ++j) {
65            for (int k = 0; k < c1; ++k) {
66                mult[i][j] += first[i][k] * second[k][j];
67            }
68        }
69    }
70}
71
72void display(int mult[][10], int r1, int c2) {
73
74    printf("\nOutput Matrix:\n");
75    for (int i = 0; i < r1; ++i) {
76        for (int j = 0; j < c2; ++j) {
77            printf("%d  ", mult[i][j]);
78            if (j == c2 - 1)
79                printf("\n");
80        }
81    }
82}
83