帮我改以下代码的错#include <stdio.h> int main() { int mem_page_num=3; int seq_len=17; int page_seq[] = { 7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 2, 1, 2, 0, 1 }; int result = opt_missing_page_num(page_seq, seq_len, mem_page_num); printf("%d", result); return 0; } int opt_missing_page_num(int page_seq[], int seq_len, int mem_page_num) { int mem_page[mem_page_num]; int page_fault = 0; int next_use[mem_page_num]; int i, j, k, max_next_use; for (i = 0; i < mem_page_num; i++) { mem_page[i] = -1; next_use[i] = seq_len; } for (i = 0; i < seq_len; i++) { int page = page_seq[i]; int found = 0; for (j = 0; j < mem_page_num; j++) { if (mem_page[j] == page) { found = 1; next_use[j] = seq_len; break; } } if (!found) { int victim = -1; for (j = 0; j < mem_page_num; j++) { int use_time = next_use[j]; if (use_time < seq_len && (victim == -1 || use_time < next_use[victim])) { victim = j; } } mem_page[victim] = page; next_use[victim] = seq_len; page_fault++; } for (j = 0; j < mem_page_num; j++) { int page2 = mem_page[j]; if (page2 != -1) { found = 0; max_next_use = -1; for (k = i + 1; k < seq_len; k++) { if (page_seq[k] == page2) { found = 1; max_next_use = k; break; } } if (!found) { max_next_use = seq_len; } next_use[j] = max_next_use; } } } return page_fault; }

这段代码中的问题是缺少函数的声明，需要在main函数前面加上函数声明：

#include <stdio.h> 

int opt_missing_page_num(int page_seq[], int seq_len, int mem_page_num); 

int main() { 
    int mem_page_num=3; 
    int seq_len=17; 
    int page_seq[] = { 7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 2, 1, 2, 0, 1 }; 
    int result = opt_missing_page_num(page_seq, seq_len, mem_page_num); 
    printf("%d", result); 
    return 0; 
} 

int opt_missing_page_num(int page_seq[], int seq_len, int mem_page_num) { 
    int mem_page[mem_page_num]; 
    int page_fault = 0; 
    int next_use[mem_page_num]; 
    int i, j, k, max_next_use; 
    for (i = 0; i < mem_page_num; i++) { 
        mem_page[i] = -1; 
        next_use[i] = seq_len; 
    } 
    for (i = 0; i < seq_len; i++) { 
        int page = page_seq[i]; 
        int found = 0; 
        for (j = 0; j < mem_page_num; j++) { 
            if (mem_page[j] == page) { 
                found = 1; 
                next_use[j] = seq_len; 
                break; 
            } 
        } 
        if (!found) { 
            int victim = -1; 
            for (j = 0; j < mem_page_num; j++) { 
                int use_time = next_use[j]; 
                if (use_time < seq_len && (victim == -1 || use_time < next_use[victim])) { 
                    victim = j; 
                } 
            } 
            mem_page[victim] = page; 
            next_use[victim] = seq_len; 
            page_fault++; 
        } 
        for (j = 0; j < mem_page_num; j++) { 
            int page2 = mem_page[j]; 
            if (page2 != -1) { 
                found = 0; 
                max_next_use = -1; 
                for (k = i + 1; k < seq_len; k++) { 
                    if (page_seq[k] == page2) { 
                        found = 1; 
                        max_next_use = k; 
                        break; 
                    } 
                } 
                if (!found) { 
                    max_next_use = seq_len; 
                } 
                next_use[j] = max_next_use; 
            } 
        } 
    } 
    return page_fault; 
}