(@例说明执行频度 X=X+ y 2. for i=1 to n do x=x+ y repeat 3. for j=1 to n do f。orj=1 to n do X=X+ y repeat repeat例 说明执行频度 1. x=x+ y; 2. for i=1 to n do x=x+ y repeat 3. for i=1 to n do for j=1 to n do x=x+ y repeat repeat 1 n n 2