//ex1.cpp
#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;
}

//ex2.cpp
#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;
}
 

//ex3.cpp
#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("%f,%lf",&x,&y);
    printf(
 
"%f,%lf\n",x,y);
    
    return 0;
}

//ex4.cpp
//判斷字元型別
#include<stdio.h>
int main(){
    char x;
    
    x = getchar();
    
    if(x>='0'&&x<='9')
        printf("x是數字字元\n",x);
    else if(x>='a'&&x<='z'||x>='A'&&x<='Z')
        printf("x是英文字母\n",x);
    else
        printf("x是其他字元\n",x);
    
    return 0;
} 

//ex5.cpp
#include<stdio.h>
int main(){
    char ans1,ans2;
    
    printf("複習了沒？（輸入y或Y表示複習了，輸入n或N表示沒有複習）：");
    ans1=getchar();
    
    getchar();
    
    printf("\n動手敲程式碼了沒？（輸入y或Y表示敲了，輸入n或N表示沒有敲）：");
    ans2=getchar();
     
     if(ans1=='y'||'Y'&&ans2=='y'||'Y')
     printf("\n羅馬不是一天建成的:)\n");
     else
     printf("\n羅馬不是一天毀滅的。。。\n");
     
     return 0;
}

//ex6.cpp
#include<stdio.h>
#include<math.h> 
int main(){
    int n,q,s,a1;
    scanf("%d",&n);
    q=2,a1=1;
    s=a1*(1-pow(q,n))/(1-q);
    printf("s=%d\n",s);
    
    return 0;
}