CODEWITHSUNDEEP
cfile
Fopa Léon Constantin
Fopa Léon Constantin

Reputation: 12363

C code for reading numbers from a file

I want to read all integers from a file and put them all in an array

 ./prog input.txt

where input.txt contains for example the following numbers

 -6 8 9 0 45 54 67 0 12
 23 3 -25 12 67 6 9 -9

How to do this without knowing the number of integer in advance

thanks for anyone answer !

Upvotes: 0

Views: 4172

Answers (2)

Eduard Luca
Eduard Luca

Reputation: 6602

Something like this. (Not tested)

while(!feof(inFile)){ //inFile is your pointer to the file opened with fopen()
    fscanf(inFile,"%d",&a[i]); //a is your array
    i++;
}

This way in your i variable you will have the number of items in the file (+1) and you'll get all numbers in the array.

Upvotes: 1

pmg
pmg

Reputation: 108978

  • initialize a memory area
    • read number in a loop and
    • if needed use realloc on the memory area
    • add number to array
  • [use memory area]
  • release memory

You will need to keep a count of how many elements are already in the array and the maximum number of elements it can have (so you know when it's time to reallocate).

Upvotes: 1

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