试修改下面生产者一消费者问题解法中的错误。 producer: begin repeat producer an item in nextp; wait(mutex); wait(full); buf

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问题 试修改下面生产者一消费者问题解法中的错误。
    producer:
    begin
    repeat
    producer an item in nextp;
    wait(mutex);
    wait(full);
    buffer(in):=nextp;
    signal(mutex);
    until false;
    end
    consumer:
    begin
    repeat
    wait(mutex);
    wait(empty);
    nextc:=buffer(out);
    out:=out+1;
    signal(mutex);
    consumer item in nextc;
    until false;
    end

选项

答案 producer: begin repeat producer an item in nextp; wait(mutex); wait(full); /*应为wait(empty),而且还应该在wait(mutex)的前面*/ buffer(in):=nextp; /*缓冲池数组游标应前移:in:=(in+1)mod n;*/ signal(mutex); /*signal(full);*/ until false; end consumer: begin repeat wait(mutex); wait(empty); /*应为wait(full),而且还应该在wait(mutex)的前面 */ nextc:=buffer(out); out:=out+1: /*考虑循环,应改为:out:=(out+1)mod n;*/ signal(mutex): /*signal(empty);*/ consumer item in nextc: until false; end

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