problem with c program

Hi
i have written a program but am stuck with one last bit.
i need to display minuses and pluses for the temps entered. see below for example
-5 -----

-1 -

0

1 +

10 ++++++++++

12 ++++++++++++

14 ++++++++++++++

22 ++++++++++++++++++++++

I have it working so for all positives numbers the pluses will be displayed but i cant get the minuses to display
If you run the program and enter the temps both positive and negative you will see only the pluses display and not the minuses.

Can someone help me get the minuses to display.  Code is attached

Thanks

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

main()
{
    int menu();
    void input_temps(int temp_array[], int n);
    void display_temps(int temps[], int num);
    void calculate_avg( int temps[], int no_of_temps);
    void calculate_min_max(int temps[], int no_of_temps);
    void convert_to_fahrenheit( int temps[], int no_of_temps);
    void sort_temps(int temps[], int no_of_temps);
    void temps_graph(int temps[], int no_of_temps);

    int* temps;
    int no_of_temps, no_of_bytes;
    int option;

        printf("Enter the Number of Temperature Readings  ");
        scanf("%d", &no_of_temps);
        no_of_bytes=no_of_temps*sizeof(int);
        temps=(int*)malloc(no_of_bytes);

        input_temps(temps, no_of_temps);


        display_temps(temps,no_of_temps);

 do
 {
    option=menu();

    switch (option)
    {
    case 0:
      break;
    case 1:
        calculate_avg(temps,no_of_temps);
        break;
    case 2:
        calculate_min_max(temps,no_of_temps);
        break;
    case 3:
        convert_to_fahrenheit(temps, no_of_temps);
    break;
    case 4:
        sort_temps(temps, no_of_temps);
    break;
    case 5:
        temps_graph(temps, no_of_temps);
    break;

    }
}
    while (option!=0);

}

int menu()
{
    int opt;
    printf("\n");
    printf ("1. Calculate the average temperature \n");
    printf ("2. Calculate the minimum and maximum temperature \n");
    printf ("3. Display the temperatures in Fahrenheit \n");
    printf ("4. Sort the temperatures \n");
    printf ("5. Display the Celcius temperatures graphically \n");
    printf ("0. Exit\n\n");
    scanf  ("%d",&opt);
    printf("\n");
    return opt;
}
void input_temps(int temp_array[], int n)
{
    int i;
    printf("Enter %d temperatures \n\n",n);
    for (i=0; i<n; i++)
      scanf("%d", &temp_array[i]);
}
void display_temps(int temps[], int num)
{
    int i;
    printf("\n\nThe temperatures you entered are ");
    for (i=0;i<num;i++ )
    printf("%d, ",temps[i]);

    printf("\n\n");
}

void calculate_avg(int temps[], int no_of_temps)
{
int i, total;
float avg;
total = 0;

for(i = 0; i <no_of_temps; i++)
{
total += temps[i];

}

avg = (float)total/(float)no_of_temps;

printf("\n\nThe average temperature is  %.2f" , avg);
printf("\n\n");
}

 void calculate_min_max(int temps[], int no_of_temps)
{
  int max = temps[0];
  int min = temps[0];
  int i;

  for (i = 0; i < no_of_temps; i++)
     {
      if (temps[i] > max)
        {
          max = temps[i];
        }
      else if (temps[i] < min)
        {
          min = temps[i];
        }
    }
  printf ("\n\nThe maximum Temperature is : %d\n", max);
  printf ("The minimum temperature is : %d\n", min);
  printf("\n\n");

}
void convert_to_fahrenheit(int temps[], int no_of_temps)
{
    int i;
    double f;

    for (i = 0; i < no_of_temps; i++)

{
         f=temps[i]*9.0/5.0+32.0;

printf("\n\nThe temperature %d in Celsius is %lf in Fahrenheit\n\n" , temps[i], f);

}
}

void sort_temps(int temps[], int no_of_temps)
{
   int i, temperature;
   char sorted;
        printf("Unsorted Temperatures:");
        for (i = 0; i < no_of_temps; i++)
        printf("%d ", temps[i]);

    do
    {
        sorted=1;
        for (i = 0; i < no_of_temps; i++)
        {
            if (temps[i+1] < temps[i])
            {
                temperature=temps[i];
                temps[i] = temps [i+1];
                temps [i+1]= temperature;
                sorted=0;
            }
        }
    }
    while (!sorted);

    printf("\n\nSorted Temperatures:");
    for (i = 0; i < no_of_temps; i++)
        printf ("%d ", temps[i]);
    printf ("\n\n");
}
void temps_graph(int temps[], int no_of_temps)
{
    int i;
    char symbol;

    for (i = 0; i < no_of_temps; i++)
{


    printf("\n%d ",temps[i]);

    for (symbol = 0; symbol < temps[i]; symbol++)
    {
        {
            if (symbol<0)
            {
            putchar ('-');
            }
            else if (symbol>0)
            {
                putchar ('+');
            }
        }

    }
}
}

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