Question

我正在尝试从C. The problem I'm having is that my random numbers aren't going from the range I expect (from 0 to 2047) as this example says that it will中的数组中选择随机索引。只是从查看索引我得到它似乎我得到的数字从1000-1200而不是所需的范围。

这是调用rand（）的代码。

#define MAXPAGES         2048    // maximum number of processes in the system

//until we have a node, pick random indexes.
while(node == NULL){
    table_index = rand() % MAXPAGES;
    node = table[table_index];
    if(node){
       fprintf(stderr, "%d\n", table_index);
       if(node->current_pages > 0) break;
       else node = NULL;
    }
}

我在主要功能中只调用一次srand。

int main(int argc, char** argv) {
    int i;
    int simulations = 100000;
    // initialize the process hash table
    if(argc > 1){
        removal_algorithm  = atoi(argv[1]);
        if(argc == 3) simulations = atoi(argv[2]);
    }

    srand(time(NULL));
    for (i = 0; i < MAXPAGES; i++) table[i] = NULL;

    printf("Random replacement MMU simulation on %d simulations started\n", simulations);
    Simulate(simulations);
    printf("Random MMU simulation completed. only writing page faults:,");
    printf("%d, read / write page faults: %d, total page faults: %d\n", read_miss, write_miss, read_miss + write_miss);
}

示例序列。

Answer 1

您的代码显然只打印那些table[table_index]不为空的索引。如果table[0]为空，则永远不会打印0。即此代码不一定证明rand()的行为。相反，它的行为可能主要取决于table的内容。

stdlib.h rand（）％范围不是从0到范围

1 个答案: