void error message in c

Question

#include <stdio.h>

void simpleInterest (double Princ, double Rate, int Time)
{
      double value;
      value = Princ*Rate*Time;
      return value;
}

int main (int argc, char*argv[])
{
      printf("the value is %d", simpleInterest (100,0.01,5))
}

I can't seem to find what is wrong with my code, i'm really new to c just started today actually, i get an error code saying:

simpleInterest: warning return with a value, in function returning void [enabled by default]

what does that actually mean ? what is actually wrong with my code ?

Answer 1

void simpleInterest (double Princ, double Rate, int Time)
    {
          double value;
          value = Princ*Rate*Time;
          return value; //void function should not return anything
    } 

You need to declare and define your function with double return type.

 double simpleInterest (double Princ, double Rate, int Time)
    {
          double value;
          value = Princ*Rate*Time;
          return value; 
    } 

When you return double you should use %f format specifier in printf statement.Other wise it invokes undefined behavior.

printf("the value is %f", simpleInterest (100,0.01,5))