#include"iostream"#include"iomanip"using namespace std;int f(int i,int n){    if(i==1||i==n) return 1;    else return f(i-1,n-1)+f(i,n-1);    return 0;}void main(){    int n;    cout<<"打印杨辉三角前n行:";    cin>>n;    for(int i=1;i<=n;i++){        for(int m=n-1;m>=i;m--)        {               cout<<"   ";        }        for(int j=1;j<=i;j++)        {               cout<
     
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