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166: Mainline

Recall that C's if statement executes its embedded statement if the value of the Boolean expression is not 0. C has no complimentary statement, which might be called unless, if it existed, for which the embedded statement is executed when the value of the Boolean expression is 0.

One way to get the effect of the nonexistent unless statement is by prefacing the Boolean expression with the not operator, !. Thus, the following tests are equivalent:

if (ratio < 10) printf ("It is cheap!\n"); 
if (!(ratio >= 10)) printf ("It is cheap!\n");