why assigning three == signs inside if statement in c doesnot work? [duplicate]

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• Usage of greater than, less than operators 6 answers

i have a code like this: int naxes1[1] = {6}; int naxes2[1] = {6}; int naxes3[1] = {6};

if (naxes1[0]  == naxes2[0] == naxes3[0])
    printf("first doesnot work\n");

if (naxes1[0]  == naxes2[0] && naxes1[0]== naxes3[0])
    printf("second works\n");

why?