Compare integers in an array

Hello. I'm new to C programming and attending a web course. We learned about arrays but I still struggle to understand how to compare values in an array. Say I have

Code:

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{2 4 6 1 5}

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and I want to compare index 0 with index 1,2,3,4 not by typing

Code:

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array[0]

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and

Code:

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array[1]

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but

Code:

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array[k] with array[?]

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.

Thank you in advance, Mike

I'm going to assume that you're trying to compare "every element to every other element" or some such. This is a use case that occurs frequently in dealing with arrays.

To do this, you'll want two variables. Traditionally, these are i and j. When you get to a third variable, that will be k. (This comes from Fortran, where variable type (integer, real, etc) was determined by the first letter.)

Code:

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extern SomeType a[];
extern size_t alen;

for (int i = 0; i < alen; ++i) {
    for (int j = i + 1; i < alen; ++j) {
        // do something with a[i], a[j]       
    }
}

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Quote:

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Originally Posted by emikash

Hello. I'm new to C programming and attending a web course. We learned about arrays but I still struggle to understand how to compare values in an array. Say I have

Code:

---

{2 4 6 1 5}

---

and I want to compare index 0 with index 1,2,3,4 not by typing

Code:

---

array[0]

---

and

Code:

---

array[1]

---

but

Code:

---

array[k] with array[?]

---

.

Thank you in advance, Mike

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Code:

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int main(void)
{
    int array[5] = {2, 4, 6, 1, 5};
    int j, k;

    for (j =0; j < 5; j++)
      for (k = 0; k < 5; k++)
      {
          char compare;
          if (array[j] < array[k])
            compare = '<';
          else if (array[j] > array[k])
            compare = '>';
          else
              compare = '=';

          printf(array[%d] %c array[%d]\n", j, compare, k);
      }

}

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