用c語言求圓的面積

1. 誰幫我用c語言編一個程序求任意圓的面積

#include "stdio.h"
#define PI 3.14159
int main()
{
float nR;
float nArea;
printf("請輸入圓的半徑:");
scanf("%f",&nR);
nArea = PI*nR*nR;
printf("圓的面積是：%f\n",nArea);
return 0;
}

2. C璇璦涓鍦嗙殑闈㈢Н鎬庝箞奼傦紵

璁＄畻鍦嗙殑闈㈢Н鐨勭紪紼嬫槸錛

#include <stdio.h>

#define N 3.14 //鍦嗗懆鐜

float S(float r)//璁＄畻闈㈢Н

{

float s;

s=N*r*r;

return s;

}

void main()

{

float r;

printf("璇瘋緭鍏ュ渾鐨勫崐寰:");

scanf("%f",&r);

printf(" 璇ュ渾鐨勫崐寰勬槸錛%f",S(r));

}

3. c語言怎麼求圓的面積

#include"stdio.h"
#include"process.h"
#definePI3.1415926;
doublecalcAreaOfCircleByR(doubler);//聲明函數計算圓面積r為半徑
doublecalcAreaOfCircleByD(doubled);//聲明函數計算圓面積d為直徑
intmain(intargc,char*argv[])
{
doubler=1.0;
doubled=2.0;
printf("半徑r=%g的圓面積%g
",r,calcAreaOfCircleByR(r));
printf("直徑d=%g的圓面積%g
",d,calcAreaOfCircleByD(d));
printf("
");
system("pause");
return0;
}
doublecalcAreaOfCircleByR(doubler)//計算圓面積r為半徑
{
return(r)*(r)*PI;
}
doublecalcAreaOfCircleByD(doubled)//計算圓面積d為直徑
{
return(d*d/4)*PI;
}