Thread: Need help with file in C programming

Hey guys, i'm studying files in C and when i do the following assignment, I get stuck.

Problem: There are N boxes(1 ≤ N ≤ 1000). Each box has its own capacityCi (1 ≤ Ci ≤ 10000, 1 ≤ i ≤ N). Boxes are used to carry water from far away. Given the amount of water in each box. Calculate the minimum number of boxes needed to carry.

Input: from file WATER.INP with structure:
- the first line gives N (number of boxes)
- the following N lines, each line has 2 parameters: Bi and Ci (0<= Bi <= Ci) which is th information of the i th box (Bi is amount of water, Ci is the capacity).There is at least one space between Bi and Ci.
Output: create a file WATER.OUT that contains the minimum number of boxes needed.

For examle:
WATER.INP
4
0 1
4 5
0 2
1 2

WATER.OUT
1

I know how to print down a text file to screen, but not the files contains numbers. And I don't know how to access to each number in that file to use for my program.

Hope you guys can help.
Many thanks.

Here's an idea:
1. Open the file with fopen()
2. Read the first line with fgets() to obtain N - the number of additional rows to be expected.
3. Iteratively call fgets() to obtain Bi and Ci (you can either loop while fgets() returns non-null value, or loop N times).

The above assumes the input file is in the correct format, and also assumes that you only need help with reading the file, not with the algorithm itself.

Can u give me an example of how you get the value N from the input file? I mean the full code of it.

Wow, this thread is now in the Projects and Recruitment forum...someone moved it here. In that case, I'll take the job!

Code:

#include<stdio.h>


int main() {
    int N;
    float number;
    
    
    FILE * fptr;
    fptr = fopen("/fullpathname/Water.txt", "r");
    if (fptr == NULL) return 1;
    
    fscanf(fptr,"%d",&N);
    printf("The number of values is %d\n", N);
    
    while ( fscanf(fptr, "%f", &number) != EOF) 
        printf("Number: %f \n", number);
    
    return 0;
}