// Multiply rows of A by columns of B.
type Matrix = Vec<Vec<i32>>;
// Print a 2D array (matrix)
fn print_matrix(arr2d: &Matrix) {
for row in arr2d {
for val in row {
print!("{:4}", val);
}
println!();
}
}
// Multiply matrices A and B into C
fn multiple_matrix(a: &Matrix, b: &Matrix, c: &mut Matrix) {
for i in 0..c.len() {
for j in 0..c[i].len() {
for k in 0..a[i].len() {
c[i][j] += a[i][k] * b[k][j];
}
}
}
}
fn main() {
// Create matrices
let a: Matrix = vec![
vec![1, 8, 5],
vec![6, 7, 1],
vec![8, 7, 6],
];
let b: Matrix = vec![
vec![4, 8, 1],
vec![6, 5, 3],
vec![4, 6, 5],
];
// Initialize result matrix C with zeros
let mut c: Matrix = vec![vec![0; b[0].len()]; a.len()];
// c[0][0] = (a[0][0] * b[0][0]) + (a[0][1] * b[1][0]) + (a[0][2] * b[2][0])
print_matrix(&a);
println!();
print_matrix(&b);
println!();
multiple_matrix(&a, &b, &mut c);
print_matrix(&c);
}
/*
run:
1 8 5
6 7 1
8 7 6
4 8 1
6 5 3
4 6 5
72 78 50
70 89 32
98 135 59
*/
