Question

I want to read integers from a file like this:

9 5  1847
6    9 5
 87     
2   48  1
7 1 5 4 2
6  17   8
   95  
4 6    8 
5192  7 4

For example 1,8,4,7 are to be taken as different numbers.

I tried this way:

 #define MAXLINE 1024

 void readFile(FILE *file){
     char line [MAXLINE];
     int j;
     while(fgets(line,MAXLINE,file)!=NULL){
         for(j=0;j<9;j++){              
             int a = atoi(&line[j]);
             printf("%d \n",a);         
         }      
     }
 }

But it is reading 1847 as only one number.

Answer 1

enum { MAXLINE = 1024 };

void readFile(FILE *file)
{
    char line[MAXLINE];
    while (fgets(line, sizeof(line), file) != 0)
    {
        char *str = line;
        int j;
        int pos;
        while (sscanf(str, "%1d%n", &j, &pos) == 1)
        {
            printf("%d\n", j);
            str += pos;
        }
    }
}

The %1d part of the format reads a single digit (but also skips blanks). The %n is in C89 and reports the position where the scan is in the string; it is not counted as a conversion (hence the comparison with 1).