c - 我的代码中出现未知错误

Question

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define Pi 3.14159265358979323846
#define MAX_DATA 20


double Find_GrowthRate(double Data_6hr[MAX_DATA],double Data_24hr[MAX_DATA]);
double Find_DoublingTime(double GrowthRate[MAX_DATA]);


int main()
{
   int i;
   double t1;
   double Data_6hr[MAX_DATA] = {2.3,3.3,4.3,5.3,6.3,7.3,8.3,9.3,10.3,11.3,12.3,13.3,14.3,15.3,16.3,17.3,18.3,19.3,20.3,21.3};
   double Data_24hr[MAX_DATA] = {4.2,5.2,6.2,7.2,8.2,9.2,10.2,11.2,12.2,13.2,14.2,15.2,16.2,17.2,18.2,19.2,20.2,21.2,22.2,23.2};
   Find_GrowthRate(Data_6hr,Data_24hr);
   double *GrowthRate;
   printf("Growth Rates\n");
   for(i=0;i<MAX_DATA;i++){
      printf("%lf \n",*(GrowthRate+i));
   }
   Find_DoublingTime(GrowthRate);
   printf("Average Doubling Time");
   printf("%lf", t1);
   return 0;
}

double Find_GrowthRate(double Data_6hr[MAX_DATA], double Data_24hr[MAX_DATA])
{
   int i;

   double *GrowthRate;
   GrowthRate = (double*)malloc(MAX_DATA*sizeof(double));
   for(i=0;i<MAX_DATA;i++){
      double PopulationSize_t1 = (Pi * pow((Data_6hr[i]/ 2),2));
      printf("%lf\n",PopulationSize_t1);
      double PopulationSize_t2 = (Pi * pow((Data_24hr[i]/ 2),2));
      printf("%lf\n",PopulationSize_t2);
      double x = ((PopulationSize_t2 - PopulationSize_t1) / PopulationSize_t1);
      *(GrowthRate+i) = x;
   }
   printf("Growth Rates\n");
   for(i=0;i<MAX_DATA;i++){
      printf("%lf \n",*(GrowthRate+i));
   }

   return GrowthRate;

}

我收到的错误是:-

错误:返回类型 'double *' 时类型不兼容，但预期为 'double

想知道我需要对我的代码进行哪些更改，以及我是否可以改进我的代码。

Answer 1

函数 Find_GrowthRate 被声明为具有返回类型 double

double Find_GrowthRate(double Data_6hr[MAX_DATA],double Data_24hr[MAX_DATA]);
^^^^^^

但是在函数定义中，函数返回类型为 double *

的对象

double Find_GrowthRate(double Data_6hr[MAX_DATA], double Data_24hr[MAX_DATA])
{
   int i;

   double *GrowthRate;
   //...
   return GrowthRate;
          ^^^^^^^^^^

}

此外，由于指针GrowthRate 指向的动态分配的内存未被释放，因此存在内存泄漏。

在这个循环中

   double *GrowthRate;
   printf("Growth Rates\n");
   for(i=0;i<MAX_DATA;i++){
      printf("%lf \n",*(GrowthRate+i));
   }

使用了导致未定义行为的未初始化变量 GrowthRate。

同样的问题存在于未初始化的变量t1

 double t1;
 //...
 printf("%lf", t1);