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POInfinite-loop when reading from a text file
 

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  1. POInfinite-loop when reading from a text file
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    <p>I have read several questions on this site and managed to write the code below which reads data from a file (shown before the code, below). The problem is that the code gets in an infinite loop in the <code>do {...} while</code> segment, indicating that it does not "recognise" the newline char. I have no idea what to do. Also when I pass from the command-line the filename to read, it crashes. Could someone please help?</p> <p>Input File Format:</p> <pre><code>1 3 3 3 1 23588769 1 2 1 4 4 9 4788939 3 2 1 2 2 4 5 5 2 3 3 1 4 3 5 17215766 5 2 1 1 4 5 5 4 </code></pre> <p>Code:</p> <pre><code>int main (int argc, char *argv[]) { FILE *fp = NULL; if (argc == 1) { fp = stdin; } else { fp = fopen( argv[1], "r" ) ; } fp = fopen( argv[1], "r" ) ; if (fp == NULL) exit(2); for(i=0; i&lt;42; i++) KEYS_I_HAVE[i]=0; fscanf( fp,"%d",&amp;num_start_keys); fscanf(fp, "%d",&amp;doors); KEYS_FOR_DOORS = (int*)malloc(doors*sizeof(int)); POINTS = (int*)malloc(doors*sizeof(int)); for(i=0; i&lt;doors; i++) { KEYS_FOR_DOORS[i]=0; POINTS[i]=0; } MAP = malloc(doors*sizeof(int)); for(i=0; i&lt;43; i++) MAP[i] = malloc(43*sizeof(int)); for(i=0; i&lt;doors; i++) { for (j=0; j&lt;43; j++) MAP[i][j] = 0; } for(i=0; i&lt;(doors+1); i++) { j=0; if(i==0) { do { fscanf(fp,"%d",&amp;temp); printf("%d",temp); KEYS_I_HAVE[temp]++; a=fgetc(fp); }while(a != '\n'); } else { do { fscanf(fp,"%d",&amp;temp); if (j==0) sum += temp; else { if (j==1) KEYS_FOR_DOORS[i-1] = temp; else { if(j==2) POINTS[i-1]=temp; else MAP[i-1][temp]++; } } a=fgetc(fp); j++; if (feof(fp) ) break; }while( a != '\n' ); } } fclose(fp); </code></pre>
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    1. USumläute
    1. USAlexis S.
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    2. PO
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    1. COTwo immediate problems: If you don't provide an argument to the program, it still tries to open `argv[1]`. And if you use `stdin` as input you still close the file at the end of the program.
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      1. USSome programmer dude
    2. COOther than that, I recommend you use `while (fgets(...) != NULL)` to read lines, and then parse the contents of the line.
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      1. USSome programmer dude
    3. COWhen you have time, please fix the formatting of the code segment, so that the content on Stackoverflow will continue to be of high quality. Thanks.
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      1. USSabuncu
 

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