C function returns wrong value - c

Question

float a, b;
float sa() { return a;};
int main() {
a = 10;
b = sa();
printf("%f", b);
return 0;
}
This is a simplified version of my code.
I believe the program should print 10 but it gives me really small numbers like -65550, not always the same but very alike.
I have used the debugger to check the value of variabe a right before it is returned and it is 10, so the function returns 10, but b is set to something like -65550. I don't understand why this happens.
I'd appreciate some intell.
Thanks in advance.
Here is the full code:
#include <stdlib.h>
#include <stdio.h>
#include <math.h>
#include <time.h>
int dimensiuni, nrBitiSolutie, bitiPeDimensiune, gasitInbunatatire, nrRulari;
float limInf, limSup, precizie, valoareFunctie, minim, minimNou, T;
char solutie[100000];
float solutieReala[100];
void generateRandomSolution();
void bitesToFloat();
void rastrigin();
void rosenbrock();
float nextFirstFit();
float nextBestFit();
void main() {
int k;
T = 10;
gasitInbunatatire = 1;
srand ( time(NULL) );
printf("Introduceti numarul de dimensiuni: ");
scanf("%d", &dimensiuni);
printf("Introduceti limita inferioara si cea superioara: ");
scanf("%f%f", &limInf, &limSup);
printf("Introduceti precizia: ");
scanf("%f", &precizie);
//calculam numarul de biti necesari ca sa reprezentam solutia
nrBitiSolutie = dimensiuni * ceil(log(limSup-limInf * pow(10, precizie)))/log(2.0);
bitiPeDimensiune = nrBitiSolutie/dimensiuni;
//generam o solutie random
generateRandomSolution();
bitesToFloat();
rastrigin();
minim = valoareFunctie;
printf("Pornim de la %f\n", minim);
while( (nrRulari < 10000) && (T > 0.001)) {
minimNou = sa(); //error occurs here. sa() returns about 200 but minimNou is set to -65550
if (minimNou < minim) {
printf("Minim nou: %f\n", minimNou);
minim = minimNou;
T *= 0.995;
}
nrRulari++;
}
printf("Minimul aproximat: %f\n", minim);
system("pause");
}
void generateRandomSolution() {
int l;
for (l = 0; l < nrBitiSolutie; l++) solutie[l] = rand()%2;
}
void bitesToFloat() {
int i, parcurse = 1, gasite = 0;
int variabila = 0;
float nr;
for (i = 0; i < nrBitiSolutie; i++) {
variabila = variabila<<1 | (int)solutie[i];
if(parcurse == bitiPeDimensiune) {
nr = (float)variabila / (float)pow(2, bitiPeDimensiune);
nr *= limSup-limInf;
nr += limInf;
nr *= pow(10, precizie);
nr = (int)nr;
nr /= pow(10, precizie);
parcurse = 0;
solutieReala[gasite++] = nr;
variabila = 0;
}
parcurse++;
}
}
void rastrigin() {
int i;
valoareFunctie = 10 * dimensiuni;
for (i = 0; i < dimensiuni; i++) {
valoareFunctie += pow((float)solutieReala[i], 2) - 10 * (float)cos(2 * 3.14 * (float)solutieReala[i]);
}
}
void rosenbrock() {
int i;
valoareFunctie = 0;
for (i = 0; i < dimensiuni - 1; i++) {
valoareFunctie += 100 * pow((solutieReala[i+1] - pow(solutieReala[i], 2)), 2) + pow((1-solutieReala[i]), 2);
}
}
float sa() {
int j;
for (j = 0; j < nrBitiSolutie; j++) {
solutie[j] = solutie[j] == 0 ? 1 : 0;
bitesToFloat();
rastrigin();
if (valoareFunctie < minim) return valoareFunctie;
else if ( (rand()/INT_MAX) < exp((minim - valoareFunctie)/T) )
return valoareFunctie;
else solutie[j] = solutie[j] == 0 ? 1 : 0;
}
return minim;
}
I have marked where the error occurs with error occurs here comment

Answer 1

You simplified the code incorrectly. In your simplification, you defined sa() before calling it. But in your full program, you call sa() before defining it. In the absence of a declaration, functions are assumed to return int. Since your function actually returns a float, the result is undefined. (In this case, you will read a garbage value from the top of the floating point stack and then the floating point stack will underflow, and things go downhill from there.)