Thread: sum and product of two matrix in C (with functions)

I have to write a program in C which finds the sum and the product of two matrix.
I wrote the functions but I get stucked at calling them in main .I don't know which variable is for rows and columns of result matrix.

Code:

Code:

#include <stdio.h>
void enterMatrix(int a[][10], int rows, int columns)
{
    int i,j;
    for(i=0;i<rows;i++)
    {
        for(j=0;j<columns;j++)
        {
            printf("a(%d,%d)=",i,j);
            scanf("%d",&a[i][j]);
        }
    }
}
void displayMatrix(int a[][10], int rows, int columns)
{
    int i,j;
    for(i=0;i<rows;i++)
    {
        for(j=0;j<columns;j++)
        {
            printf("%d", a[i][j]);
            printf(" ");
        }
        printf("\n");
    }
}
void matrixSum(int a[][10], int b[][10], int c[][10], int rows, int columns)
{
    int i,j;
    for(i=0;i<rows;i++)
    {
        for(j=0;j<columns;j++)
        {
            c[i][j]=a[i][j]+b[i][j];
        }
    }
}
void matrixProduct(int a[][10], int b[][10], int c[][10], int rows, int columns)
{
    int i,j,k;
    for(i=0;i<rows;i++)
    {
        for(j=0;j<columns;j++)
        {
            c[i][j]=0;
            for(k=0;k<columns;k++)
            {
                c[i][j]+=a[i][k]*b[k][j];
            }


        }
    }
}
int main(void)
{
    int a[10][10], b[10][10], sum[10][10], product[10][10];
    int rowsA,columnsA,rowsB,columnsB;
    printf("Number of rows for matrix A: \n");
    scanf("%d",&rowsA);
    printf("Number of columns for matrix A: \n");
    scanf("%d",&columnsA);
    printf("Number of rows for matrix B: \n");
    scanf("%d",&rowsB);
    printf("Number of columns for matrix B: \n");
    scanf("%d",&columnsB);
    printf("Enter first matrix: \n");
    enterMatrix(a,rowsA,columnsA);
    printf("Show first matrix: \n");
    displayMatrix(a,rowsA,columnsA);
    printf("Enter second matrix: \n");
    enterMatrix(b,rowsB,columnsB);
    printf("Show second matrix: \n");
    displayMatrix(b,rowsB,columnsB);


    if((rowsA==rowsB) && (columnsA==columnsB))
    {
        matrixSum(a,b,sum, ???, ???);
        printf("The sum matrix is: \n");
        displayMatrix(sum, ???, ???);
    }
    else
    {
        printf("Wrong information.");
    }
    if((rowsA==columnsB) && (rowsB==columnsA))
    {
        matrixProduct(a,b,product,???,???);
        printf("The product matrix is \n");
        displayMatrix(product,???,???);
    }
    return 0;
}