How to find if element is not in an array

Question

Does anyone know of an easy way in C to check if a an element is NOT in a given array?

I think it would be fairly easy to determine if an element IS in an array by looping through it and seeing if an element is equal to the element I’m looking for.

But how do you determine if it’s NOT in there? For example, say I were using a nested loop… setting the condition if [i] != [j] don’t tell me if the element in [i] is nowhere in [j]…it just says that they’re not currently equal on that current iteration.

I believe Python has a function that lets you search If something is In or Not In a List or other collection. But does C?

Answer 1

No, C does not have such a function. The only way to check is to search the entire array. Most efficient is to just run a for loop or while loop and check every element. If a match is found, set a flag and break out of the loop. If not found, the loop ends on it's own and you can process a "not found" code block afterwards.

pseudocode:

int found = 0;
for( i = 0;i < array_size; i++)
{
    if( array[i] == target)  // edit: had the wrong "=" operator before changing it.  my bad. 
    { 
        found = 1;
        break;
    }
}

if (found)
{
    printf("There's a match. \n");    
}
else
{
    printf("No match. \n");
}

You might want to turn it into a function if it's something that's reused.

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