Multiple file program - c

Question

Following code is meant to read values and save them to an array. Just that when I build and run my code my file isn't found. I'm basically trying to make a program that takes a data point from a file and inputting it into my code. When it runs it shows that the file isn't found though correctly inputting the file name.
#include <stdio.h>
#include <stdlib.h>
//function prototype
void calc_results(int time[], int size);
void read_temps(int temp[]);
//set size of array as global value
#define SIZE 25
int main ()
{
rand();
//Declare temperature array with size 25 since we are going from 0 to 24
int i, temp[SIZE];
read_temps(temp);
//Temperature for the day of October 14, 2015
printf("Temperature conditions on October 14, 2015:\n");
printf("\nTime of day\tTemperature in degrees F\n\n");
for (i = 0; i < SIZE; i++)
printf( "%d \t\t%d\n",i,temp[i]);
//call the metod calc_results(temp, SIZE);
calc_results(temp, SIZE);
//pause the program output on console until user enters a key
system ("PAUSE"); return 0;
}
/**The method read_temps that takes the input array temp
and prompt user to enter the name of the input file
"input.txt" and then reads the tempertures from the file
for 24 hours of day */
void read_temps(int temp[])
{
char fileName[50];
int temperature;
int counter=0;
printf("Enter input file name : ");
//prompt for file name
scanf("%s",fileName);
//open the input file
FILE *fp=fopen(fileName, "r");
//check if file exists or not
if(!fp)
{
printf("File doesnot exist.\n");
system ("PAUSE"); //if not exit, close the program
exit(0);
}
//read temperatures from the file input.txt until end of file is encountered
while(fscanf(fp,"%d",&temperature)!=EOF)
{
//store the values in the temp array
temp[counter]=temperature;
//incremnt the coutner by one
counter++;
}
//close the input file stream fp
fclose(fp);
}
void calc_results(int temp[], int size)
{
int i, min, max, sum = 0;
float avg;
min = temp[0];
max = temp[0];
//Loop that calculates min,max, sum of array
for (i = 0; i < size; i++)
{
if (temp[i] < min)
{
min = temp[i];
}
if (temp[i] > max)
{
max = temp[i];
}
sum = sum + temp[i];
}
avg = (float) sum / size;
//open an external output file
FILE *fout=fopen("output.txt","w");
//Temperature for the day of October 14, 2015
fprintf(fout,"Temperature conditions on October 14, 2015:\n");
fprintf(fout,"\nTime of day\tTemperature in degrees F\n\n");
//write time of day and temperature
for (i = 0; i < SIZE; i++)
{
fprintf( fout,"%d \t\t%d\n",i,temp[i]);
}
printf("\nMin Temperature for the day is : %d\n", min);
printf("Max Temperature for the day is :%d\n", max);
printf("Average Temperature for the day is : %f\n", avg);
//write min ,max and avg to the file "output.txt"
fprintf(fout,"\nMin Temperature for the day is : %d\n", min);
fprintf(fout,"Max Temperature for the day is :%d\n", max);
fprintf(fout,"Average Temperature for the day is : %f\n", avg);
//close the output file stream
fclose(fout);
}