我的第二个结构没有返回正确的值

Question

我是编码的新手，只是想知道为什么我的第二个结构“ DtoS”在计算时不返回正确的值？我正在编写代码，将电阻值从星形转换为三角形，反之亦然。

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
struct StarAndDelta 
    float del1, del2, del3, star1, star2, star3;
};
typedef struct StarAndDelta Struct; 

Struct StoD(float R1, float R2, float R3)
{
    Struct s;

    s.del1 = (((R1*R2)+(R2*R3)+(R3*R1))/R3);
    s.del2 = (((R1*R2)+(R2*R3)+(R3*R1))/R2);
    s.del3 = (((R1*R2)+(R2*R3)+(R3*R1))/R1);
    return(s);

}

Struct DtoS(float RA, float RB, float RC)
{
    Struct d;

    d.star1 = RA*RB/RA+RB+RC;
    d.star2 = RA*RC/RA+RB+RC;
    d.star3 = RB*RC/RA+RB+RC;

    return(d);
}


float LimitsOfResistors (float R) 
{
    do 
    {
        if((R<1000 || R>1000000))   
        {
            printf("Please enter a value within the range: ");  
            scanf("%f", &R);
        }

    }
    while((R<1000 || R>1000000)); 
    return(R);  
}


int main(void)
{
    char str[2];    

    do  
    {

        float r, q, s, r1, q1, s1;      
        Struct delta;                   


        printf("\nPress s for Star \nPress d for Delta \nPress q to exit \n");      t
        printf("Please enter an input of what calculation you would like to be carried out: "); 

        fgets(str, 2, stdin);   


        if(strcmp(str, "q") == 0)   
        {
            printf("Have a great day. Bye! ");  
            return(0);      
        }


        if(strcmp(str, "s") == 0)   
        {
            printf("Please enter value a for R1, which is between 1K and 1M: ");
            scanf("%f", &r);
            r1 = LimitsOfResistors(r);
            printf("Please enter value a for R2, which is between 1K and 1M: ");        
            scanf("%f", &q);                                                            
            q1 = LimitsOfResistors(q);                                                  
            printf("Please enter value a for R3, which is between 1K and 1M: ");        
            scanf("%f", &s);                                                            
            s1 = LimitsOfResistors(s);


            delta = StoD(r1, q1, s1);
            printf("The value of Ra is: %.2f", delta.del1);


            delta = StoD(r1, q1, s1);                               
            printf(" The value of Rb is: %.2f", delta.del2);        

            delta = StoD(r1, q1, s1);
            printf(" The value of Rc is: %.2f", delta.del3);

        }

        if(strcmp (str, "d") == 0)                                  
        {
            printf("Please enter value a for RA, which is between 1K and 1M: ");
            scanf("%f", &r);
            r1 = LimitsOfResistors(r);                                              
            printf("Please enter value a for RB, which is between 1K and 1M: ");    
            scanf("%f", &q);                                                       
            q1 = LimitsOfResistors(q);                                           
            printf("Please enter value a for RC, which is between 1K and 1M: ");    
            scanf("%f", &s);
            s1 = LimitsOfResistors(s);


            delta = DtoS(r1, q1, s1);
            printf("The value of R1 is: %f", delta.del1);                 

            delta = DtoS(r1, q1, s1);
            printf("The value of R2 is: %f", delta.del2);

            delta = DtoS(r1, q1, s1);
            printf("The value of R3 is: %f", delta.del3);

        }


    }
    while(strcmp(str, "d") || strcmp(str, "s") ); 

}

Answer 1

（您（很可能）有一个复制粘贴错误，导致未定义的行为。

在if(strcmp(str, "s") == 0)的块中，您具有：

printf("The value of Ra is: %.2f", delta.del1);                              
printf(" The value of Rb is: %.2f", delta.del2);        
printf(" The value of Rc is: %.2f", delta.del3);

在if(strcmp (str, "d") == 0)的块中，您具有：

printf("The value of R1 is: %f", delta.del1);                 
printf("The value of R2 is: %f", delta.del2);
printf("The value of R3 is: %f", delta.del3);

在if(strcmp (str, "d") == 0)的块中，您应该打印star字段：

printf("The value of R1 is: %f", delta.star1);                 
printf("The value of R2 is: %f", delta.star2);
printf("The value of R3 is: %f", delta.star3);

而且，也不必调用StoD和DtoS三次。一次就足够了：

delta = StoD(r1, q1, s1);
printf("The value of Ra is: %.2f", delta.del1);                              
printf(" The value of Rb is: %.2f", delta.del2);        
printf(" The value of Rc is: %.2f", delta.del3);

delta = DtoS(r1, q1, s1);
printf("The value of R1 is: %f", delta.star1);                 
printf("The value of R2 is: %f", delta.star2);
printf("The value of R3 is: %f", delta.star3);