Функции (Расчет определителя матрицы)

#include <stdio.h>
#include <conio.h>
#include <math.h>
#include <alloc.h>
 
float mat(float **a, int n)
{ int i,j;
float s,d,f,g;
  i=1;
  j=1;
s=((a[i+2][j+2]*a[i+3][j+3]-a[i+2][j+3]*a[i+3][j+2])*a[i+1][j+1]-(a[i+2][j+1]*a[i+3][j+3]-a[i+2][j+3]*a[i+3][j+1])*a[i+1][j+2]+(a[i+2][j+1]*a[i+3][j+2]-a[i+2][j+2]*a[i+3][j+1])*a[i+1][j+3]);
d=((a[i+2][j+2]*a[i+3][j+3]-a[i+2][j+3]*a[i+3][j+2])*a[i+1][j]-(a[i+2][j]*a[i+3][j+3]-a[i+2][j+3]*a[i+3][j])*a[i+1][j+2]+(a[i+2][j]*a[i+3][j+2]-a[i+2][j+2]*a[i+3][j])*a[i+1][j+3]) ;
f=((a[i+2][j+1]*a[i+3][j+3]-a[i+2][j+3]*a[i+3][j+1])*a[i+1][j]-(a[i+2][j]*a[i+3][j+3]-a[i+2][j+3]*a[i+3][j])*a[i+1][j+1]+(a[i+2][j]*a[i+3][j+1]-a[i+2][j+1]*a[i+3][j])*a[i+1][j+3]);
g=((a[i+2][j+1]*a[i+3][j+2]-a[i+2][j+2]*a[i+3][j+1])*a[i+1][j]-(a[i+2][j]*a[i+3][j+2]-a[i+2][j+2]*a[i+3][j])*a[i+1][j+1]+(a[i+2][j]*a[i+3][j+1]-a[i+2][j+1]*a[i+3][j])*a[i+1][j+2]);
n=(s*a[i][j])-(d*a[i][j+1])+(f*a[i][j+2])+(g*a[i][j+3]);
 
return(n);
}
 
 
void main ()
{
clrscr();
float **b,z;
int i,j;
b=(float**)malloc(80*(sizeof(float*)));
 
for (i=1;i>4;i++)
{
 for (j=1;j>4;j++)
 {
   scanf("%d",&b[i][j]);
 }
}
z=mat(b,4);
printf("%f",z);
getch();
}