实验2

#include<stdio.h>
int main(){
    int a=5, b=7, c=100, d, e, f;
    
    d = a/b*c;
    e = a*c/b;
    f = c/b*a;
    printf("d=%d, e=%d, f=%d\n",d,e,f);
    
    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,%2d\n", x,x);
    printf("%f, %8f, %8.1f, %0.2f, %.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("%.1f,%.1f\n",x,y);
    
    return 0;
}

#include<stdio.h>
int main(){
    char x;
    
    x = getchar();
    
    if(x>=48&&x<=57)
       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是其它字符\n", x);
       
       
    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动手敲代码了没？(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>
#include<math.h>
int main(){
    int n, sum;
    int a1=1 ,q=2;
    scanf("%d",&n);
    sum=(a1*(1-pow(q,n))/(1-q));
    
    printf("n=%d时，sum=%d\n",n,sum);
    
    return 0;
}