#include <stdio.h>
#include <math.h>

typedef struct _vector_2d {
    float x, y;
} vector2;

int main() {
    vector2 a = { 2, 3 };
    vector2 b = { 4, 5 };
    
    printf("Vector A: (%.2f, %.2f)\n", a.x, a.y);
    printf("Vector B: (%.2f, %.2f)\n", b.x, b.y);
    printf("CosΘ: %.2f\n", (a.x*b.x+a.y*b.y)/(sqrt(a.x*a.x+a.y+a.y)*sqrt(b.x*b.x+b.y*b.y)));
}