在`for(int i=1;i<=m;i++) `这个循环后加大括号
你的代码等同于
```cpp
for (int i = 1; i <= m; ++i) {
cin >> x >> y;
}
join(x,y,f);
```
by xiaosuan @ 2023-05-23 18:30:58
@[xiaosuan](/user/529574) 还请大佬细说（迷糊.jpg）
by BL8083 @ 2023-05-28 17:50:33
你可以运行下面两个代码试一下：
```c++
#include <cstdio>
using namespace std;
int main() {
int i;
for (i = 0; i < 10; ++i)
printf("i == %d\n", i);
printf("i * i == %d\n", i * i);
return 0;
}
```
```c++
#include <cstdio>
using namespace std;
int main() {
int i;
for (i = 0; i < 10; ++i) {
printf("i == %d\n", i);
printf("i * i == %d\n", i * i);
}
return 0;
}
```
by xiaosuan @ 2023-05-28 18:51:00