目录
- 1. printf与scanf
- 2.sqrt函数
- 3.π
- 4.三位数反转
- 5.三整数排序
1. printf与scanf
#include<stdio.h>
int main()
{printf("%lf\n",8.0/5.0);printf("%lf\n",8/5.0);printf("%lf\n",8/5);printf("%d\n",8.0/5.0);printf("%d\n",8/5);
}
//1.600000
//1.600000
//0.000000
//-1717986918
//1
对于printf来说,后面是什么类型,前面就必须对应相应的类型
浮点数可以用%lf输出,也可以用%f输出,而且默认保留小数点后六位
#include<stdio.h>
#include<math.h>
int main()
{double a;scanf("%f",&a);printf("%lf",a);}//1.1
//0.000000
对于scanf来说,double类型只能用%lf
2.sqrt函数
#include<stdio.h>
#include<math.h>
int main()
{printf("%f\n",sqrt(3));printf("%d\n",sqrt(3));printf("%f\n",sqrt(3.0));
}
//1.732051
//-396866390
//1.732051
由此可见,sqrt函数返回值是实数型,而且函数的参数可以是实数或整数
sqrt函数的四舍五入:int m = floor (sqrt(n)+0.5);
3.π
const double pi = acos(-1.0);
4.三位数反转
#include<stdio.h>
#include<math.h>
int main()
{int n;scanf("%d",&n);printf("%d%d%d",n%10,n/10%10,n/100);return 0;
}
#include<stdio.h>
#include<math.h>
int main()
{int n;scanf("%d",&n);printf("%03d",n%10*100+n/10%10*10+n/100);return 0;
}
两种方法,告诉我们整体与部分的思想
5.三整数排序
#include<stdio.h>
#include<math.h>
int main()
{int a,b,c,t;scanf("%d%d%d",&a,&b,&c);if(a>b){t=a;a=b;b=t;}if(a>c){t=a;a=c;c=t;}if(b>c){t=b;b=c;c=t;}printf("%d %d %d",a,b,c);return 0;
}
把a,b,c大小固定,然后分类讨论,比猜测可能方案简便