How to read a line of integers?

This is a discussion on How to read a line of integers? within the C Programming forums, part of the General Programming Boards category; If i want to read 10 integers from a file i would write this: Code: int main(){ int i; freopen("numbers.txt","r",stdin); ...

  1. #1
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    How to read a line of integers?

    If i want to read 10 integers from a file i would write this:

    Code:
    int main(){
    
        int i;
    
        freopen("numbers.txt","r",stdin);
    
        for(i = 0; i <= 10; i++){
            scanf("%d",&i);
            printf("%d",i);
        }
        fclose(stdin);
    
        return 0;
    }
    But how to write a loop if i don't know how many integers will be in a file?

  2. #2
    SAMARAS std10093's Avatar
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    Take a look at fread .
    It will return NULL when it reads out the file....

  3. #3
    qny
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    Do a "forever loop" (with a break inside to get out)

    Code:
    for (;;) {
        /* ... */
        if (NEED_TO_EXIT_LOOP) break;
        /* ... */
    }

  4. #4
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    it would be better to use fopen since freopen works mostly when the file had already been opened.

  5. #5
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    Code:
    FILE *fp = fopen("numbers.txt", "rb");
    
    int k = 0;
    while(  k < 10)
    {
         fscanf(fp, "%d", &i);
          k++;
    }

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