help me to get rid of these errors to find inverse of a matrix in 'C'

#include<stdio.h>
#include<math.h>
float detrm(float[][],float);
void cofact(float[][],float);
void trans(float[][],float[][],float);
main()
{
	float a[25][25],k,d;
	int i,j;
	printf("ENTER THE ORDER OF THE MATRIX:\n");
	scanf("%f",&k);
	printf("ENTER THE ELEMENTS OF THE MATRIX:\n");
	for(i=0;i<k;i++)
	{
		for(j=0;j<k;j++)
		{
			scanf("%f",&a[i][j]);
		}
	}
	d=detrm(a,k);
	printf("THE DETERMINANT IS=%f",d);
	if(d==0)
	printf("\nMATRIX IS NOT INVERSIBLE\n");
	else
	cofact(a,k);
}
/******************FUNCTION TO FIND THE DETERMINANT OF THE MATRIX************************/
 
float detrm(float a[25][25],float k)
{
	float s=1,det=0,b[25][25];
	int i,j,m,n,c;
	if(k==1)
	{
		return(a[0][0]);
	} 
	else
	{
		det=0;
		for(c=0;c<k;c++)
		{
			m=0;
			n=0;	
			for(i=0;i<k;i++)
			{
				for(j=0;j<k;j++)
				{
					b[i][j]=0;
					if(i!=0&&j!=c)
					{
						b[m][n]=a[i][j];
						if(n<(k-2))
							n++;
						else
						{	
							n=0;
							m++;
						}
					}
				}
			}
			det=det+s*(a[0][c]*detrm(b,k-1));
			s=-1*s;
		}
	}
	return(det);
}
 
/*******************FUNCTION TO FIND COFACTOR*********************************/ 
 
void cofact(float num[25][25],float f){ 
float b[25][25],fac[25][25]; 
int p,q,m,n,i,j; 
for(q=0;q<f;q++){
for(p=0;p<f;p++){
m=0;
n=0;
for(i=0;i<f;i++){
for(j=0;j<f;j++){
b[i][j]=0;
if(i!=q&&j!=p)
{
b[m][n]=num[i][j];
if(n<(f-2))
n++;
else{
n=0;
m++;
}
}
}
}
fac[q][p]=pow(-1,q+p)*detrm(b,f-1);
}
}
trans(num,fac,f);
}
 
/*************FUNCTION TO FIND TRANSPOSE AND INVERSE OF A MATRIX**************************/ 
 
void trans(float num[25][25],float fac[25][25],float r){ 
int i,j;
float b[25][25],inv[25][25],d;
for(i=0;i<r;i++){
for(j=0;j<r;j++){
b[i][j]=fac[j][i];
}
}
d=detrm(num,r);
inv[i][j]=0;
for(i=0;i<r;i++){
for(j=0;j<r;j++){
inv[i][j]=b[i][j]/d;
}
}
printf("\nTHE INVERSE OF THE MATRIX:\n");
for(i=0;i<r;i++){
for(j=0;j<r;j++){
printf("\t%f",inv[i][j]);
} 
printf("\n");
} 
}

c:3: error: array type has incomplete element type
c:4: error: array type has incomplete element type
c:5: error: array type has incomplete element type
c:5: error: array type has incomplete element type
c: In function ‘main’:
c:20: error: type of formal parameter 1 is incomplete
c:25: error: type of formal parameter 1 is incomplete
c: In function ‘cofact’:
c:105: error: type of formal parameter 1 is incomplete
c:105: error: type of formal parameter 2 is incomplete