实验2

#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char** argv) {
    int num;
    
    scanf("%d",&num);
    printf("2049%04d\n",num);
    
    scanf("%d",&num);
    printf("2049%04d\n",num);
    
    scanf("%d",&num);
    printf("2049%04d\n",num);
    
    return 0;
}

  #include <iostream>
  
  /* run this program using the console pauser or add your own getch, system("pause") or input loop */
  
  int main(int argc, char** argv) {
      int x=1234;
      float f = 123.456;
     double m = 123.456;
     char ch = 'a';
     char a[] = "你好，世界";     
     int y=3, z=4;
     
     printf("%d ,%d\n", y, z);
     printf("y=%d, z=%d\n", y, z);
     printf("%8d,%2d\n", x, x);
     printf("%f, %8d, %8.1f, %0.2f, %.2e\n", f, f, f, f,f);
     printf("%lf\n", m);
     printf("%c\n", ch);
     printf("%s\n%15s\n%10.5s\n%2.5s\n%.3s\n", a, a, a, a, a);
     
     return 0;
 }

#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char** argv) {
    double x,y;
    char c1,c2,c3;
    int a1,a2,a3;
    
    
    scanf("%1d%1d%1d",&a1,&a2,&a3);
    printf("%d,%d,%d\n", a1, a2, a3);
    scanf("%c%c%c",&c1,&c2,&c3);
    printf("%c%c%c\n", c1, c2, c3);
    scanf("%lf,%lf",&x,&y);
    printf("%f,%lf\n",x,y);

    return 0;
}

#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char** argv) {
    char ans1, ans2;
    
    printf("复习了没？（输入y或Y表示复习了，输入n或N表示没有复习）：");
    ans1 = getchar();
    getchar(); //消除回车键对输入的影响 
    printf("\n动手敲代码了吗？（输入y或Y表示敲了，输入n或N表示没有敲）：");
    ans2 = getchar();
    
    if((ans1=='y'||ans1=='Y')&&(ans2=='y'||ans2=='Y'))
      printf("\nROME CITY was not  built in one single day.\n");
    else 
      printf("\nROME CITY was not destoryed in one single day.\n");
            
     
    return 0;
}

 #include <iostream>
 
  /* run this program using the console pauser or add your own getch, system("pause") or input loop */
  
  int main(int argc, char** argv) {
      char x;
      
      x = getchar();
      
     if(x<='9'&&x>='0')
       printf("%c是数字字符\n",x);
    else if((x<='z'&&x>='a')||(x<='Z'&&x>='A'))
       printf("%c是字母字符\n",x);
    else
       printf("%c是其他字符\n",x);
      
     return 0;
 }

#include <iostream>
  #include <math.h>
  /* run this program using the console pauser or add your own getch, system("pause") or input loop */

  int main(int argc, char** argv) {
     int n,s,q;
     while(1){
     
     scanf("%d",&n);
    q = pow(2,n);
    s = 2*(1-q)/(1-2)+1;
    printf("n=%d时,sum=%d\n",n,s);
 }
    return 0;
 }