cin和scanf的不同处在哪里

P5735 【深基7.例1】距离函数

ww4445 @ 2021-01-10 21:44:28

#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;

int main(){
    double a1,a2,b1,b2,c1,c2;
    //scanf("%lflf%lf%lf%lf%lf",&a1,&a2,&b1,&b2,&c1,&c2);
    cin>>a1>>a2>>b1>>b2>>c1>>c2;
    double s=sqrt((a1-b1)*(a1-b1)+(a2-b2)*(a2-b2))+sqrt((b1-c1)*(b1-c1)+(b2-c2)*(b2-c2))+sqrt((a1-c1)*(a1-c1)+(a2-c2)*(a2-c2));
    printf("%.2lf\n",s);
    return 0;
}

如上，cin无问题，scanf莫名结果都为0，是吧空格读上了吗？

by FunnyCreatress @ 2021-01-10 21:48:02

%lflf

iee

by CGDGAD @ 2021-01-10 21:48:35

@ww4445 ？

%lflf是什么

by EuphoricStar @ 2021-01-10 21:48:59

@ww4445 少了个 %

正确代码：

#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;

int main(){
    double a1,a2,b1,b2,c1,c2;
    scanf("%lf%lf%lf%lf%lf%lf",&a1,&a2,&b1,&b2,&c1,&c2);
    double s=sqrt((a1-b1)*(a1-b1)+(a2-b2)*(a2-b2))+sqrt((b1-c1)*(b1-c1)+(b2-c2)*(b2-c2))+sqrt((a1-c1)*(a1-c1)+(a2-c2)*(a2-c2));
    printf("%.2lf\n",s);
    return 0;
}

by ww4445 @ 2021-01-13 14:10:25

@NSObject （。_。）

by MarvinWang @ 2021-05-29 08:47:20

@NSObject lf=long float=double类型

by CGDGAD @ 2021-05-29 09:58:40

@wasitaratisaw 那个是两个 lf

（草，四个半月以前的帖子怎么被拿出来考古了）

by MarvinWang @ 2021-05-29 22:32:04

。。。