Question

2的n次方用C语言怎么编写程序？？

Answer 1

#include<math.h>
main()
{double i;/*要用双精度型，因为pow函数的原形是double pow(double x,double y)*/
printf("input n:");
scanf("%lf",&i);/*双精度型的格式符是%lf*/
printf("2^%d=%d\n",(int)i,(int)pow(2.0,i));/*在i和pow(2.0,i)是双精度型的，加上(int),把它们强制转换成整型*/
}

Answer 2

#include <stdio.h>

double power(int n);
void main()
{
printf("%f %f %f",power(2),power(3),power(100));//测试

}

double power(int n) //传递n ，默认n>=0
{
double result = 1;

while(n)
{
result = result * 2.0; //乘以2.0 注意不是2，否则计算要出错
n--;
}
return result;
}

Answer 3

/* Note:Your choice is C IDE */
#include"stdio.h"
#include"math.h"
int main() {
int A=2;
int N;
printf("input the N: ");
scanf("%d",&N);
printf("2^N = %g\n",pow(A,N));
return 0;
}

算是搞去来了，我也是新手~~

Answer 4

#include<stdio.h>
#include<math.h>
main()
{
int n;
long j;
scanf("%d",&n);
j=pow(2,n);
printf("2^n=%d\n",j);
}