I have used CodeBlocks compiler for debugging purpose. But you can use any C programming language compiler as per your availability.

#include <stdio.h>

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;
}

Result:

Enter rows and column for first matrix: 2

3

Enter rows and column for second matrix: 3

2

Enter elements of matrix 1:

Enter elements a11: 1

Enter elements a12: 2

Enter elements a13: 3

Enter elements a21: 4

Enter elements a22: 5

Enter elements a23: 6

Enter elements of matrix 2:

Enter elements b11: 2

Enter elements b12: 5

Enter elements b21: 6

Enter elements b22: 8

Enter elements b31: 2

Enter elements b32: 1

Output Matrix:

20  24  

50  66