Thread: Passing an array to a function

Im trying to pass the array A into the function 'determinant' in order to calculate its determinant. However I keep getting the following error: cannot convert `float (*)[((unsigned int)((int)x))]' to `float (*)[2]' for argument `1' to `float determinant(float (*)[2])'

Here is my code:

#include <stdio.h>

float determinant(float a[2][2]);

main ()
{
int col, row, x=2, y=2;
float A[y][x], B[y],detA;


printf("Enter Matrix A: ");

for(row=0 ; row<y; row++)
{
for(col=0 ; col<x ; col++)
scanf("%f", &A[row][col]);
}

printf("You entered:\n");

for(row=0 ; row<y; row++)
{
for(col=0 ; col<x ; col++)
printf("[%f]", A[row][col]);
putchar('\n');
}

printf("Enter Matrix B: ");

for(row=0 ; row<x; row++)
scanf("%f", &B[row]);


printf("You entered:\n");

for(row=0 ; row<y; row++)
printf("[%f]\n", B[row]);

detA = determinant(A);
printf("%f", detA);

}


/* Calculate determinant of matrix A */

float determinant(float a[2][2])
{
float det;
det = a[0][0]*a[1][1] - a[0][1]*a[1][0];
return det;
}


Im editing and compiling using Dev-C++ 4.9.9.2
Any help would be great, Thanks.

Ah you're right, it works now when I replace x and y with 2.
Thanks

i would of used a pointer for it and then passed the length of the x and y.

Mostly the same code as before but I'm trying to use functions and calling by reference to input the matrices. But I'm still getting a similar error as before, and I can't see where I'm going wrong. Thanks.

12 cannot convert `float (*)[2][2]' to `float* (*)[2]' for argument `1' to `void getmatrixA(float* (*)[2])'

13 cannot convert `float (*)[2]' to `float**' for argument `1' to `void getmatrixB(float**)'

Code:

#include <stdio.h>

void getmatrixA(float *A[2][2]);
void getmatrixB(float *B[2]);
float determinant(float a[2][2]);

main ()
{
     int col, row, x=2, y=2;
     float A[2][2], B[2], Ak[2][2], detA; 
     
     getmatrixA(&A);
     getmatrixB(&B);
     
     detA = determinant(A);
     printf("Determinant of A: %f\n", detA);
     
     for(row=0 ; row<y; row++)
     {
      for(col=0 ; col<x ; col++)
       {
        if(col=0)
        Ak[row][col]=B[row];
        else
        Ak[row][col]=A[row][col];
       }
     }

     printf("Ak:\n");
  
     for(row=0 ; row<y; row++)
     {
      for(col=0 ; col<x ; col++)
        printf("[%f]", Ak[row][col]);
      putchar('\n');
     }
}

void getmatrixA(float *A[2][2])
{    
     int col, row;
     
     printf("Enter Matrix A: ");
     
     for(row=0 ; row<2; row++)
     { 
      for(col=0 ; col<2 ; col++)
        scanf("%f", &A[row][col]);
     }

     printf("You entered:\n");
  
     for(row=0 ; row<2; row++)
     {
      for(col=0 ; col<2 ; col++)
        printf("[%f]", A[row][col]);
      putchar('\n');
     }
}

void getmatrixB(float *B[2])
{
     int col, row;
     
     printf("Enter Matrix B: ");
     
     for(row=0 ; row<2; row++)
      scanf("%f", &B[row]);
     

     printf("You entered:\n");
  
     for(row=0 ; row<2; row++)
        printf("[%f]\n", B[row]);
}
      

/* Calculate determinant of matrix A */ 

float determinant(float a[2][2])
{
  float det;          
  det = a[0][0]*a[1][1] - a[0][1]*a[1][0];
  return det;
}