Syntax error before = sign

[abrown07]

 

double gravityFactor(double mass, double radius)
{  
     
     double gf;
    
      gf=((mass/Me)/((radius/Re)*(radius/Re)));
     
      return gf;     
}  

double escapeVelocity(double mass, double radius)
{
    
    double ev;
     
     ev=(sqrt((2*(G)*mass)/radius))/1000;
     
     return ev;    
}

I have syntax error before = sign in both functions?

[jkmyoung]

What are the errors; can you post them?
Have you defined constants, G, Me and Re somewhere else?

[abrown07]

yes the constants have been defined before the main body of the program. Here is my entire program and the commented sections are just there to remind myself of what i still need to do with the program after i figure out this whole function thing.

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

#define G = 6.667428e-11
#define Me = 5.9736e24
#define Re = 6371000

double gravityFactor(double mass, double radius);
double escapeVelocity(double mass, double radius);








int main(void)
{
     double mass, radius, gf, ev;
     int unit;
     
  //          char radius[10] = {3.3022e23, 4.8685e24, 5.9736e24, '7.3477e22', '6.4185e23',
//            '1.8986e27', '5.6846e26', '8.6810e25', '1.0243e26',};
//            
//            char mass[10] = {'2439700', '6051800', '6371000', '1737100', '3396200', '71492000',
//            '60268000', '25559000', '24764000'};
//     


      printf("Select 1 for escape velocity and gravity factor.Select 2 to input values: ");
      scanf("%d", &unit);
      if(unit==1)  
      {

 //           fgets("%s", radius);
//            gravityFactor=((mass[0]/5.9736e24)/((radius[0]/6371000)*(radius[0]/6371000)));
//            
//            printf("The gravity factor of Mercury is: %.2f\n", gravityFactor);
//            
//            
           
           
           
      }  
          else if(unit==2)
          {
             	
              do
              {
                  printf("Please input the mass of your stellar bodies: ");
                  scanf("%lf", &mass);
     
                  printf("Please indicate the radius of your stellar body: ");
                  scanf("%lf",&radius);
       
   				  
   				  
                  printf("The gravity factor of this stellar body is: %.2f\n", gf);
                 //  
//                   double escapeVelocity(double m, double r);
//                   
//                   printf("The escape velocity of this stellar body is: %.2f km/s\n", ev);
//   
//                   printf("Please select 1 to calculate another planet. Press any number key to terminate.: ");
//                   scanf("%d", &unit);
//   
              }while(unit==1);
          }
  
  return 0;
  
  
}

double gravityFactor(double mass, double radius)
{       
   double gf;    
   gf =((mass/Me)/((radius/Re)*(radius/Re)));   
   return gf;     
}  


double escapeVelocity(double mass, double radius)
{    
   double ev;     
   ev =(sqrt((2*(G)*mass)/radius))/1000;    
   return ev;    
}

this is what my compiler gives me

assignment4.c: In function ‘gravityFactor’ :
assignment4.c:8 1: error: syntax error before ‘=’ token
assignment4.c:8 1: error: syntax error before ‘=’ token
assignment4.c:8 1: error: syntax error before ‘=’ token
assignment4.c: In function ‘escapeVelocity ’:
assignment4.c:8 9: error: syntax error before ‘=’ token

[jkmyoung]

c doesn't understand numbers in the form 6.667428e-11.
Convert them into floats or doubles.

[abrown07]

this is not fix the problem. and it was accepting them as inputs and giving me the correct outputs before i tried defining them

[weaknessforcats]

#define G = 6.667428e-11
#define Me = 5.9736e24
#define Re = 6371000

G, Me and Re should be doubles rather than a #define value.

That is, 6.667428e-11 is not a double. It is the value of a double.