subscripted value is neither an array nor pointer nor vector at line sum+=matrix[i][j]
int matrix(int matrix[],int m, int n) //function
{
int sum=0,i,j; //to add the matrix elements
for(int i = 0;i< m ; i ++)
{
for(int j=0;j<n; j ++)
{
Blockquote
sum+=matrix[i][j]; //error
}
}
return sum
}