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("%lf\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("%.1lf,%.1lf\n",x,y);

    return 0;
}

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

    x = getchar();

    if(x>='1'&&x<='9')
        printf("%c是数字字符\n", x);
    else if(x>='a'&&x<='z'||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();  // 从键盘输入一个字符，赋值给ans1

    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 sum,n,q=2;
    scanf("%d",&n);
    sum=1*(1-pow(q,n))/(1-q);
    printf("sum=%d\n",sum);
    return 0;
}