h.if

强大的数学工具包

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        "if-statement"
        SYNTAX: if(B, seq1, seq2)


        B is a boolean expression. If its value is nonzero, then seq1 
        is executed, else seq2.
        seq1 and seq2 are sequences of expressions, separated by '_' or 
        ';'. If an expression ends with '_', its output is displayed,
        if it ends with ';', its output is suppressed.
        Remark: The last expression of seq1 or seq2 must not be
                terminated by '_' and need not be terminated by ';'.
                If you want its output to be suppressed, terminate it
                by ';'.
        The sequences may be empty.


        Example 1: (correct)

                if(a mod 2, b = (a - 1)/2, b = a/2)


        Example 2: (correct)

                if( (3||t)&&r, r=3*t;t=r^4;, t=3*r;r=t^4;)


        Example 3: (correct)

                if( 4>=t, ,r=t mod 2; e = (t-r)/2 _ t=e^3 )


        Example 4: (incorrect)

                if( 3>2, r=3 )

_ERR_NR_232