有效使用typedef？

#include<stdio.h>

// 定义一个新的数据类型名称：Position
typedef struct {
    int x;
    int y;
} Position;

// 定义一个新的数据类型名称：Distance
typedef int Distance;

int main() {
    // 使用新的数据类型名称
    Position pos1, pos2;
    Distance dist;

    pos1.x = 10;
    pos1.y = 20;

    pos2.x = 30;
    pos2.y = 40;

    dist = (pos1.x - pos2.x) * (pos1.x - pos2.x) + (pos1.y - pos2.y) * (pos1.y - pos2.y);

    printf("Distance between pos1 and pos2 is: %d\n", dist);

    return 0;
}