c++，分别用宏定义和函数求圆的面积，其中圆的半径可以为表达式？ c++,这个圆的半径可以为表达式什么意思?
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#include#define AREA(r) 3.1416*(r)*(r)using namespace std;double area(double r){return 3.1416*r*r;}int main(){double r; cin>>r; cout<<AREA(r)<<endl; cout<<area(r)<<endl; return 0;}
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#define s(r) 3.1416*(r)*(r)
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float s(float r)
{return 3.1416*r*r;
}
按照题目要求分别用宏定义和函数求圆面积的C++程序如下
用宏定义的程序
#include<iostream>
#define PI 3.14159265
#define S PI*r*r
using namespace std;
int main()
{
float r;
cout << "请输入半径：";
cin >> r;
cout << "圆的面积为：" << S << endl;
return 0;
}
用函数的程序
#include<iostream>
#define PI 3.14159265
using namespace std;
float area(float r)
{
return PI*r*r;
}
int main()
{
float r;
cout << "请输入半径：";
cin >> r;
cout << "圆的面积为：" << area(r) << endl;
return 0;
}
#include<iostream>
using namespace std;
#define pi 3.14159265
#define S1(r) pi*(r)*(r)
double S2(double r)
{ return pi*r*r;
}
int main()
{ cout<<"圆的面积为：" << S1(9+1) << endl;
//计算半径为9的轮子上套了一个厚度为1的箍后的面积
cout << "圆的面积为：" << S2(9+1) << endl;
return 0;
}
说的表达式求值应该是指宏的表达式求值吧。C++表达式求值没啥方便的函数可以用。
#include<iostream>
#define PI 3.14
#define area(r) (double(r)*double(r))*PI
int main() {
int r = 3;
std::cout << area(r) <<std::endl;
std::cout << area(r + 3) << std::endl;
std::cout << area(r * 2) << std::endl;
}
绛旓細cout << "鍦嗙殑闈㈢Н涓猴細" << area(r) << endl;return 0;}
绛旓細鍋囧畾宸茬煡鍗婂緞 r 姹傚渾闈㈢Н锛岀敤 c 璇█ 瀹 area(r) 璁＄畻 鐨勪緥瀛愶細include <stdio.h> define area(r) (3.1415926*r*r)int main(){ int i;for (i=1;i<10;i++)printf("r=%d area=%.2f\n",i,area(i));return 0;}
绛旓細perimeter=pi*r*2;printf("鐩村緞涓:%0.02f\n鍦嗙殑闈㈢Н涓:%0.03f\n鍛ㄩ暱涓:%0.02f",2*r,area,perimeter);return 0;}
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绛旓細1銆佸畾涔夌ず渚嬶細include <stdio.h> define PI 3.1415926 const double pi = 3.1415926 int main(int argc, char *argv[]){ printf("%1.7f\n",PI);printf("%1.7f\n",pi);return 0;} 2銆佹祴璇曞伐鍏凤細c-Free 3銆佸畾涔夊舰寮忥細a銆瀹忓畾涔锛#defin 鏍囪瘑绗 瀛楃涓 b銆佸父閲忓畾涔夛細const [绫诲瀷]...
绛旓細include<stdio.h> define PI 3.14 int main(){ float R,V,H;printf("璇疯緭鍏ュ崐寰勫拰楂橈細");scanf("%f%f",&R,&H);V=PI*R*R*H;printf("鍦嗘煴鐨勪綋绉负%.2lf",V);return 0;\t }
绛旓細鎬濊矾锛瀹忓畾涔鍦嗗懆鐜嘝I=3.14,閿洏杈撳叆鍗婂緞r锛岃绠PI*r*r锛屽苟杈撳嚭銆傚弬鑰冧唬鐮侊細include <stdio.h>#define PI 3.14int main(){float r,s;scanf("%f",&r);s=r*r*PI;printf("S=%.2f",s);return 0;}/*杩愯缁撴灉锛10S=314.00*/
绛旓細include <stdio.h>#include <stdlib.h>#define PI 3.14 //瀹忓畾涔pi绛変簬3.14/**闂锛 瀹氫箟涓涓暟缁鍒嗗埆瀛樺偍鍦嗘煴鐨勫簳闈㈢殑鍗婂緞r锛* 鍜屽渾鏌辩殑楂榟锛岃皟鐢鍑芥暟姹鍦嗘煴鐨勪綋绉*/float array[2]={0,0};float vs,v;//鍦嗘煴鐨勪綋绉痜loat Vb(float r, float h);int main(){ printf("璇疯緭...
绛旓細鍦嗙殑鍛ㄩ暱涓猴細15.70锛屽渾鏌辩殑浣撶Н涓猴細35.33銆傛纭唬鐮佸疄鐜帮細include <stdio.h> define PI 3.14 int main () { float r= 2.5,h=1.8;float C=0,V=0;C= PI*2*r;printf("%.2f\n",C);V = PI*r*r*h;printf("%.2f\n",V);return 0;} ...
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