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  • 工作学习 / IT杂谈 / Please help C questions- convert array to unsigned long: I have an array b[0] ='1'; ..b[6]='7'; b[7]=0; I want convert to unsigned long usl; usl = atol(buffer); there is no problem, but ... -bluewave(AlwaysStudent); 2002-2-14 {330} (#368950@0)
    Please help C questions- convert array to unsigned long: I have an array b[0] ='1'; ..b[6]='7'; b[7]=0; I want convert to unsigned long usl; usl = atol(buffer); there is no problem, but I find I have some problem in some special digit, so do we have the other way to convert an array to unsigned long digit? thanks in advance!
    • But ............. -interview(intervieweree); 2002-2-14 {239} (#368962@0)
      it really depends on your business logic,
      for instance,
      you have n elements array
      a[0]='1';
      a[1]='3';
      ....
      a[m]='\x07';
      .....
      a[n-2]='3';
      a[n-1]='\0';

      what will you do with '\x07'?
      treat it as 7 or 0 or skip it?
    • Thanks interviewer, suppose all a[i] are legal digit, 0 -- 9, do you have the other way to convert it instead of atol(); -bluewave(AlwaysStudent); 2002-2-14 (#369014@0)
      • I think each CS student has written that kind of functions several times. -goodbaby(小宝); 2002-2-14 (#369037@0)
    • sample code: -lusi(鹭鸶); 2002-2-14 {312} (#369068@0)
      char buffer[] = "123456.12";
      long number;
      number = atol(buffer); // number = 123456
      buffer[6] = '\x37'; // '7'
      number = atol(buffer); // number = 123456712;

      The things to pay attention to is atol() should less than LONG_MAX, otherwise, you'll got garbagge data in number because of overflow error.
    • Thanks lusi, This problem is done by using strtoul() function instead of atol(), -bluewave(AlwaysStudent); 2002-2-14 (#369085@0)
      • sscanf is another way. -interview(intervieweree); 2002-2-14 (#369104@0)
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