Question

/edited/
I’m new here.
I have a text file that reads:

6
<cr>
R 0
R 1
R 4
R 36
R 0
R 4

This is what I have. I want to read each line into an array so that I can convert that array into an integer so I can print only the numbers of whichever line I want later.

    #include <stdio.h>
    #include <conio.h>
    #include <math.h>
    #include <stdlib.h>
    #include <ctype.h>
    #include <string.h>


    int main()
    {
        FILE *fr;   /*declares file pointer*/
        int i, j, num[32];
        char array[32][32], input_file[32], line[32];
        printf("Enter file: ");
        fflush(stdin);
        scanf("%s", input_file);    
        fr = fopen(input_file, "r");
        for(i=0;i<32;i++)
            for(j=0;j<32;j++){
                array[i][j] = \'0';
            }
            for(i=0;i<32;i++){
                line[i] = '\0';
            }
        if(fr != NULL){

            while(fgets(line, sizeof(line), fr) != NULL){
                strcpy(array[i],line);
                    num[i] = atoi(array[i]);
                        i++;
                        printf("%d\n", num[i]);
            }
        }fclose(fr);
        else{
            perror(input_file);
        }
    }

I’m not getting any errors but it isn’t printing the right thing; this is what it prints:

-370086
-370086
-370086
-370086
-370086
-370086
-370086
-370086

Can anyone explain to me what is going wrong?

Answer 1

I think I’d handle this a bit differently. Though you haven’t stated it explicitly, I’m going to assume that the first number is telling us how many more lines of letters/numbers we’re going to read (not including the blank line). So, we want to read that, then read the rest of the lines, ignoring any leading non-digits, paying attention only to the numbers.

If that’s correct, we can simplify the code somewhat:

int num_lines;
int i;
int *numbers;

fscanf(infile, "%d", &num_lines); // read the number of lines.

numbers = malloc(sizeof(int) * num_lines); // allocate storage for that many numbers.

// read that many numbers.
for (i=0; i<num_lines; i++)
    fscanf(infile, "%*[^0123456789]%d", numbers+i);
    // the "%*[^0123456789]" ignores leading non-digits. The %d converts a number.