c语言 7-9

1、

#include <stdio.h>
#include <math.h>

int main(void)
{
    double x;
    puts("please input an double value.");
    printf("x = "); scanf("%lf", &x);
    
    printf("result: %f.
", sqrt(x));
    return 0;
}

2、函数版

#include <stdio.h>
#include <math.h>

double side(double x)
{
    return sqrt(x);
}

int main(void)
{
    double x;
    puts("please input an double value.");
    printf("x = "); scanf("%lf", &x);
    
    printf("result: %f
", side(x));
    return 0;
}

3、

#include <stdio.h>
#include <math.h>

int main(void)
{
    double area, side;
    puts("please input the area.");
    printf("area = "); scanf("%lf", &area);
    
    side = pow(area, 0.5);
    
    printf("result: %f
", side);
    return 0;
}

4、

#include <stdio.h>
#include <math.h>

int main(void)
{
    double area, side;
    puts("please input the area.");
    printf("area = "); scanf("%lf", &area);
    
    side = pow(area, (double)1/2);
    
    printf("result: %f
", side);
    return 0;
}

5、

#include <stdio.h>
#include <math.h>

int main(void)
{
    double a, b;
    puts("please input an double value.");
    printf("a = "); scanf("%lf", &a);
    
    b = pow(a, (double)1/3);
    
    printf("result: %f
", b);
    return 0;
}