Subtraction of two Matrices

/* Subtraction of two Matrices */
/* TWO_SUB.C */

# include<stdio.h>
# include<stdlib.h>

# define row 10
# define col 10

int i, j;
int row1, col1;
int row2, col2;
float mat1[row][col];
float mat2[row][col];
float mat_res[row][col];

void mat_sub(  float mat1[row][col], int, int,
float mat2[row][col], int, int,
float mat_res[row][col]);

void display(float mat[row][col], int, int);
void input(float mat[row][col], int , int);

/*  Function mat_sub */

void mat_sub(float mat1[row][col], int row1, int col1,
float mat2[row][col], int row2, int col2,
float mat_res[row][col])
{
    if(( row1 == row2) && (col1 == col2))
    {
        printf("\n Subtraction is possible and Result is as follows\n");

        for(i = 0; i < row1; i++)
            for(j = 0; j < col1; j++)
                mat_res[i][j] = mat1[i][j] - mat2[i][j];
        display(mat_res,row1,col1);
    }
    else
        printf("\n Subtraction is not possible");
    exit(0);
}

/* Output Function */

void display(float mat[row][col], int r, int c )
{
    for(i = 0; i < r; i++)
    {
        for(j = 0; j < c; j++)
        {
            printf("  %f", mat[i][j]);
        }
        printf("\n");
    }
}

/* Input function */

void input(float mat[row][col], int r, int c)
{
    for(i = 0 ; i< r; i++)
    {
        for(j = 0 ;  j<c; j++)
        {
            printf("Input Value for : %d: %d: ", i+1, j+1);
            scanf("%f", &mat[i][j]);
        }
    }
}

/* main function */

void main()
{
    int row1, col1;
    int row2, col2;
    float mat1[row][col];
    float mat2[row][col];
    float mat_res[row][col];

    printf("\n Input the row  of the matrix->1:");
    scanf("%d", &row1);
    printf("\n Input the col  of the matrix->1:");
    scanf("%d", &col1);
    printf(" Input data for matrix-> 1\n");

    input(mat1, row1, col1);
    printf("Input the row  of the matrix ->2:");
    scanf("%d", &row2);
    printf(" Input the col  of the matrix->2:");
    scanf("%d", &col2);
    printf(" Input data for matrix-> 2\n");

    input(mat2, row2, col2);
    printf("\n Entered Matrix First is as follows:\n");
    display(mat1,row1,col1);
    printf("\n Entered Matrix Two is as follows:\n");
    display(mat2,row2,col2);
    mat_sub(mat1,row1,col1,mat2,row1,col2,mat_res);
    display(mat_res,row2,col2);
}