实验2

#include <stdio.h>
int main(){
    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<stdio.h>
int main(){
    int    x = 1234;
    float  f = 123.456;
    double m = 123.456;
    char ch  = 'a';
    char a[]="hello world!";
    int y = 3 , z = 4;
    
    printf("%d %d\n", y , z);
    printf("y=%d,z=%d\n",y,z);
    
    printf("%8d\n %2d\n",x,x);
    
    printf("%f\n %8f\n %8.1f\n %0.2f\n %.2e\n",f,f,f,f,f);
    
    printf("%1f\n",m);
    
    printf("%3c\n",ch);
    
    printf("%s\n %15s\n %10.5s\n %2.5s\n %.3s\n",a,a,a,a,a);
    
    return 0;
    
    
}

 

 

#include<stdio.h>
int main(){
    double x,y;
    char c1,c2,c3;
    int a1,a2,a3;
    
    scanf("%d%d%d",&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,%f\n",x,y);
    
    return 0;
}

 

 

#include<stdio.h>
int main(){
    char ans1,ans2;
    
    printf("复习了没？(输入y或Y表示复习了,输入n或N表示没复习):");
    ans1 = getchar();
    
    getchar();
    
    printf("\n手动敲代码了没？(输入y或Y表示敲了，输入n或N表示木有敲)：");
    ans2 = getchar();
    
    if((ans1=='y'||ans1=='Y')&&(ans2=='y'||ans2=='Y'))
      printf("\n罗马是不是一天建成的:)\n");
   
   else
      printf("\n罗马不是一天毁灭的。。。\n");
      
    return 0;
     
}

 

 

 

 

 

 

 

 

#include<stdio.h>
int main(){
char x;
x = getchar();

if(x>='0'&&x<='9')
printf("%c是数字字符\n",x);

else if(x>='A'&&x<='z')
printf("%c是英文字母\n",x);

else
printf("%c是其他字符\n");

return 0;
}

 

 

 

 

 

#include<stdio.h>
#include<math.h>
main(){
    int n,s,q;
    scanf("%d",&n);
    
    if(n>=1&&n<=9)
    
    q=pow(2,n),s = 2*(1-q)/(1-2)+1,printf("n=%d时，sum=%d",n,s);

    
    
    else
    printf("The input is incorrect");
    
    return 0;
    
    
}