# How to calculate sum of random numbers in between 0 to 100 using files in C Programming?

CServer Side ProgrammingProgramming

In this program, we are adding random numbers that are generated in between 0 and 100.

After every runtime, the result of sum of random numbers is different, i.e., we get a different result for every execution.

The logic we use to calculate the sum of random numbers in between 0 to 100 is −

for(i = 0; i <=99; i++){
// Storing random numbers in an array.
num[i] = rand() % 100 + 1;
// calculating the sum of the random numbers.
sum+= num[i];
}

First, we calculate the sum of random numbers and store that sum in a file. For that open file in write open and append the sum to the array file using fprintf.

fprintf(fptr, "Total sum of the array is %d\n", sum);
//appending sum to the array file.

## Example

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define max 100
// Declaring the main function in the main header.
int main(void){
srand(time(0));
int i;
int sum = 0, num[max];
FILE *fptr;
// Declaring the loop to generate 100 random numbers
for(i = 0; i <=99; i++){
// Storing random numbers in an array.
num[i] = rand() % 100 + 1;
// calculating the sum of the random numbers.
sum+= num[i];
}
// intializing the file node with the right node.
fptr = fopen("numbers.txt", "w");
// cheching if the file pointer is null, check if we are going to exit or not.
if(fptr == NULL){
printf("Error!");
exit(1);
}
fprintf(fptr, "Total sum of the array is %d\n", sum); // appending sum to the array file.
fclose(fptr); // closing the file pointer
}

## Output

Run 1: Total sum of the array is 5224
Run 2: Total sum of the array is 5555
Note: after executing a text file is created in the same folder with number.txt
We have to open it; there we can see the sum of random numbers.