用c语言求圆的面积

1. 谁帮我用c语言编一个程序求任意圆的面积

#include "stdio.h"
#define PI 3.14159
int main()
{
float nR;
float nArea;
printf("请输入圆的半径:");
scanf("%f",&nR);
nArea = PI*nR*nR;
printf("圆的面积是：%f\n",nArea);
return 0;
}

2. C璇瑷涓鍦嗙殑闱㈢Н镐庝箞姹傦纻

璁＄畻鍦嗙殑闱㈢Н镄勭紪绋嬫槸锛

#include <stdio.h>

#define N 3.14 //鍦嗗懆鐜

float S(float r)//璁＄畻闱㈢Н

{

float s;

s=N*r*r;

return s;

}

void main()

{

float r;

printf("璇疯緭鍏ュ浑镄勫崐寰:");

scanf("%f",&r);

printf(" 璇ュ浑镄勫崐寰勬槸锛%f",S(r));

}

3. c语言怎么求圆的面积

#include"stdio.h"
#include"process.h"
#definePI3.1415926;
doublecalcAreaOfCircleByR(doubler);//声明函数计算圆面积r为半径
doublecalcAreaOfCircleByD(doubled);//声明函数计算圆面积d为直径
intmain(intargc,char*argv[])
{
doubler=1.0;
doubled=2.0;
printf("半径r=%g的圆面积%g
",r,calcAreaOfCircleByR(r));
printf("直径d=%g的圆面积%g
",d,calcAreaOfCircleByD(d));
printf("
");
system("pause");
return0;
}
doublecalcAreaOfCircleByR(doubler)//计算圆面积r为半径
{
return(r)*(r)*PI;
}
doublecalcAreaOfCircleByD(doubled)//计算圆面积d为直径
{
return(d*d/4)*PI;
}