两个for循环搞定，直接开写！

#include <iostream>
using namespace std;
 
int main() {
    int n,m;
    cin>>n>>m;
    int a[1100][1100];
    for (int i=0;i<n;i++){
        for (int j=0;j<m;j++)cin>>a[i][j];
    }
    for (int j=0;j<m;j++){
        for (int i=0;i<n;i++)cout<<a[i][j]<<" ";
        cout<<"\n";
    }
	return 0;
}