小代码

#include <iostream>
#include <stdlib.h>
#include <cmath>
using namespace std;

void switchyuju()
{
cout<<"|int x;cin>>x;                   |    "<<endl;
cout<<"| switch(x) ｛                    |"<<endl;
cout<<"| case 1:函数（）；                |"<<endl;
cout<<"| case 2:函数（）；    break ；     |"<<endl;
cout<<"|   default: cout<<\"error\n;\"}   |"<<endl;
cout<<"|char x;cin>>x;                  |    "<<endl;
cout<<"| switch(x) ｛                    |"<<endl;
cout<<"| case ‘1‘:函数（）；             |"<<endl;
cout<<"| case ‘2‘:函数（）；    break ；   |"<<endl;
cout<<"|   default: cout<<\"error\n\";}   |"<<endl;
}

void foryuju()
{cout<<"|   输出99乘法表              |"<<endl;
int a,b;
for(a=1;a<10;a++)
    {     for( b=1;b<=a;b++)
              {cout<<a<<"*"<<b<<"="<<a*b<<";"<<" ";}
          cout<<endl;
    }
}

void whileyuju()
{
cout<<"|         阶乘运算展示                     |"<<endl;
cout<<"|        0！=1；                             |"<<endl;
cout<<"|        1！=1；                             |"<<endl;
cout<<"|        2！=2*1；                           |"<<endl;
cout<<"|        3！=3*2*1=6                        |"<<endl;
cout<<"|        4！=4*3*2*1=24                     |"<<endl;
cout<<"|         阶乘运算运用                     |"<<endl;
cout<<"|想求几的阶乘（输入一个0到50的小正数）   |"<<endl;
int x,W=1;
cin>>x;
while(x>0&&x<50)     //为了防护限制在0-50
{W=W*x;x--;}
cout<<W;    //w=120   24?(1 0)
}

void  ifyuju()
 { int c;
 double d;
 d=rand()%101;
cout<<"|      输入数来看运气       |"<<endl;
cout<<"|         输入（0-100），输出结果是随机的          |"<<endl;
cin>>c;
if(c<=0){cout<<"再试一次";}
if(c<30){c=c*d;
       if(c<15) {cout<<"明天会更美好";}
       else {cout<<"明年的今天，别样风采";}
        }
if(c>=30&&c<60)
       {c=c*d;
       if(c<30){cout<<"明天会更美好";}
       else {cout<<"风景依旧在，最美是情怀";}
       }
else {cout<<"学习知识是一场场信息不对称的战争";}
}

void gotoyuju()
{
cout<<"|       我的见解   关于goto             |"<<endl;
cout<<"|      函数好用，但可避免              |"<<endl;
cout<<"|   goto语言的作用：无条件跳转          |"<<endl;
cout<<"|      以下界面展示文档                |"<<endl;
cout<<"|   { int i=1,sum=0; loop:if(i<=100)      |"<<endl;
cout<<"|{sum=sum+i; i++;  goto loop; }cout<<sum;}|"<<endl;
cout<<"|            计算累加                    |"<<endl;
cout<<"|         输入一个正整数                | "<<endl;
int i,sum=0;
cin>>i;
loop:if(i<=100)
 { sum=sum+i; i++; goto loop;  }
cout<<sum;
}

int main()
{ int X;
cout<<"---------------------------"<<endl;
cout<<"|         五大语法        |"<<endl;
cout<<"|                          |"<<endl;
cout<<"|   1.switch 2.for         |"<<endl;
cout<<"|    3.while 4.if          |"<<endl;
cout<<"|      5.goto              |"<<endl;
cout<<"---------------------------"<<endl;
cout<<"|   （1-5）选1可以总预览   |"<<endl;
cin>>X;
switch(X)
{
 case  1 : switchyuju();
    case  2 : foryuju();
     case  3 : whileyuju();
     case  4 : ifyuju();
       case 5 : gotoyuju();

 default: cout<<"error\n";
}
return(X);
}