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;
    
}

a乘b除以c，a乘c除以b，c除以b乘a

运算的先后顺序不同

#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;
}

 %d:输出整型；%8d输出整型，并占8位字符；%f:输出浮点型；%lf：输出长整型  %8.1f：保留小数后一位并占八位；%c:输出字符型；%s:输出字符串

#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,%.1lf\n",x,y);
return 0;
}

#include <stdio.h>
int main() {
    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>='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'&&ans2=='Y'||ans1=='y'&&ans2=='y'||ans1=='Y'&&ans2=='y'||ans1=='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>
int main(){
    int n,sum;
    int i = 1;
    int p = 1;
    scanf("%d",&n);
    while(i<=（n+1）){
    
    p = p*2;
    i++;
}
    sum = 1*(1-p)/(1-2);
    printf("n = %d时,sum = %d",n,sum);
    return 0;    
    
}