#include <iostream>
using namespace std; 
int main()
{
  cout << "this is the first line\n";
  cout << "this is the second line\r";
  cout << "this is the third line\n";
  cout << "this is the fouth line\r";
  cout << "this is the fifth line\n";
  cout<<"First"<<"\n"<<"Second"<<endl;
  cout<<"First123"<<"\r"<<"Second"<<endl; 
  cout<<"这是换"<<endl<<"行符";
  return 0;
}

this is the first line
this is the third linee
this is the fifth line
First
Second
Second23
这是换
行符
Presss any key to continue

#include<string.h>
#include<stdio.h>
  
int main(int argc, char *argv[])
{
  char str[128];
  while (fgets(str, 127, stdin)) {
    char *tmp = NULL;
    //去掉换行符
    if (tmp = strstr(str, "\n"))
      *tmp = '\0';
    //去掉回车符
    if (tmp = strstr(str, "\r"))
      *tmp = '\0';
    printf("---%s---\n", str);
  }
  return 0;
}