c++作业4

#include <iostream.h>
#include <cmath>
int main()
{

cout << "输出乘法表为" << endl;
for (int a=1;a<=9;a++)
{  for(int b=1;b<=a;b++)
cout << a << "*" << b << "=" << a*b << " "<< '\t';
cout<<endl;
}

return 0;
}

#include <iostream>
using namespace std;
int main()
{
int a,b,c,n(0);
for(a=0; a<=3; a++)
for(b=0; b<=3; b++)
for(c=0; c<=6; c++)
if(a+b+c==8)
n++;
cout<<"共有"<<n<<"种方法"<<endl;
}

#include<iostream>
using namespace std;
int main()
{
int n,i,j;
char ch;
cout<<"多少行的三角形?"<<endl;
cin>>n;
for(i=1;i<=n;i++)
{
for(j=n;j>=i;j--)
cout<<"  ";
for(j=1;j<=2*i-1;j++)
cout<<"*"<<" ";
cout<<endl;
}
return 0;
}