歐維斯福利設

#include <iostream>
#include <fstream>
using namespace std;
char* encode(char*);
char* decode(char*);
int main(void)
{
  char ch,str[80];
  cout<<"請輸入字串:";
  gets(str);
  cout<<"您要 1)加密 2)解密 :";
  cin>>ch;
  if(ch == '1') {
    cout<<"After encode : ";
    cout<<encode(str);
  } else if (ch == '2') {
    cout<<"After decode :";
    cout<<decode(str);
  } else
    cout<<"Unknown input";
  return 0;
}
char* encode(char *str)
{
      char *r=str;
      while(*str) {
        *str = *str + 13;
        str++;
      }  
      return r;
}
char* decode(char *str)
{
      char *r=str;
      while(*str) {
        *str = *str - 13;
        str++;
      }
      return r;
}

#include <iostream>
#include <string.h>
using namespace std;
void exclude(char*,char*);
int main(void)
{
  char str1[] = "what a wonderful world!";
  char str2[] = "wonderful";  //要去除的文字
  exclude(str1,str2);
  cout<<str1<<endl;
  return 0;
}
void exclude(char *s1,char *s2)
{
  int i, s2_len = strlen(s2);
  for(i=0; i<(int)strlen(s1) - s2_len; i++){
    if(!strncmp(s1+i, s2, s2_len)){
      strcpy(s1+i, s1+i+s2_len);
      i--;                
    }
  }
}

#include <iostream>
#define CPU "Central Processing Unit"  //定義字串
#define PI 3.14159  //定義常數
using namespace std;
int main(void)
{
    cout<<"CPU is short for "<<CPU<<endl;
    cout<<"π= "<<PI<<endl;
    return 0;
}

#include <iostream>
#define SWAP(x,y,t) (t = x, x = y, y = t)  //定義巨集
using namespace std;
int main(void)
{
    int x=3,y=4,temp;
    SWAP(x,y,temp);  //呼叫巨集
    cout<<"x = "<<x<<" y = "<<y<<endl;
 return 0;
}

#include <iostream>
#define add(x,y)      ((x)+(y))
#define minus(x,y)    ((x)-(y))
#define multiply(x,y) ((x)*(y))
#define divide(x,y)   ((double)(x)/(y))
using namespace std;
int main(void)
{
    int a,b;
    char choice;
    cout<<"請輸入您的計算式：";
    cin>>a>>choice>>b;
    switch(choice) {
        case '+': cout<<a<<"+"<<b<<"="<<add(a,b); break;
        case '-': cout<<a<<"-"<<b<<"="<<minus(a,b); break;
        case '*': cout<<a<<"*"<<b<<"="<<multiply(a,b); break;
        case '/': cout<<a<<"/"<<b<<"="<<divide(a,b); break;
        default: break;
      }
    return 0;
}

#include <iostream>      //插入標頭檔
using namespace std;

int main()  //main函式
{  //程式區塊開始
    int number;     //宣告變數
    number=0;
    cout<<number<<endl;  //將變數輸出，演示變數宣告成功
 
    return 0;
}  //程式區塊結束