空气中声速的 C 程序没有给出正确的结果

Question

The program is:

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

#define s 1086

/* Function Prototypes */
void directions(void);
float temp(void);
float calc_speed(float temp);
void display(float temp, float calc_speed);

void main()
{
    float speed;
    float tempy;

    /* Calling Functions */
    directions();
    temp();
    speed = calc_speed(tempy);
    display(tempy, speed);
}

/* Sub Program for directions */
void directions(void)
{
    printf("Enter the temperature T in farienheit> ");
}

/* Sub program for temp */
float temp(void)
{
    float t;

    scanf("%f", &t);

    return(t);
}

/* Calculating speed */
float calc_speed(float temp)
{
    float ss;

    ss = s * (sqrt(5* temp +297)/(247));

    return(ss);
}

/* Displaying Results */
void display(float temp, float calc_speed)
{
    printf("The speed of sound at %f fareinhiet is : %f", temp, calc_speed);
}

The program instructions in the link below . enter image description here

Answer 1

Your mistake is that the denominator should be inside the square root according to the instructions.

ss = s * (sqrt(5* temp +297)/(247));

should be

ss = s * (sqrt((5* temp +297)/(247)));

EDIT: Also as mentioned by the other answer your variable tempy was never initialized, you need to assign it with the return value of temp() .

tempy = temp();

Answer 2

You get the user input here

float temp(void)
{
    float t;

    scanf("%f", &t);

    return(t);
}

But you don't do anything with the returned value

 temp();
 speed = calc_speed(tempy);

So you call Cacl_speed with an uninitialized value Try

tempy = temp();
speed = calc_speed(tempy);