[已解决]急！求指导思路或者解答

优秀的Aurora

建立两个磁盘文件f1.dat和f2.dat,编程序实现以下工作:
①        从键盘输入20个整数，分别存放在两个磁盘文件中(每个文件中放10个整数)；
②        从fl.dat中读入10个数，然后存放到f2.dat文件原有数据的后面；

最佳答案

月排行榜 / 总排行榜

赚小钱

2020-5-29 02:00:24

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void write_2_files(int *nums, int count, FILE *first, FILE *second) {
    for (int i = 0; i < count; i++) {
        if (0 == (i & 1)) {
            fprintf(first, "%d ", nums[i]);
        } else {
            fprintf(second, "%d ", nums[i]);
        }
    }
}

char *read_all(FILE *f, long *length) {
    fseek(f, 0L, SEEK_END);
    *length = ftell(f);
    fseek(f, 0L, SEEK_SET);
    char *result = (char *) malloc(sizeof(char) * (*length + 1));
    memset(result, 0, sizeof(char) * (*length + 1));
    fread(result, sizeof(char), *length, f);
    return result;
}

char *read_ints(int count, FILE *from) {
    long length = 0;
    char *buffer = read_all(from, &length);
    int begin = 0, end = 0;
    for (begin = 0; begin < length; begin++) {
        char curr = buffer[begin];
        if (curr >= '0' && curr <= '9') {
            break;
        }
    }
    int found = 0;
    for (int i = begin + 1; i < length; i++) {
        char prev = buffer[i - 1];
        char curr = buffer[i];
        if (curr == ' ' && prev >= '0' && prev <= '9') {
            found += 1;
        }
        if (found >= count) {
            end = i;
            break;
        }
    }
    buffer[end] = '\0';
    char *result = strdup(buffer + begin);
    buffer[end] = ' ';
    free(buffer);
    return result;
}


void read_and_append_ints(int count, FILE *to, FILE *from) {
    char *buffer = read_ints(count, from);
    fprintf(to, " %s", buffer);
    free(buffer);
}

void foo(int *nums, const char *expected, int count) {
    FILE *first = fopen("f1.dat", "w+");
    FILE *second = fopen("f2.dat", "w+");
    write_2_files(nums, count, first, second);
    read_and_append_ints((count + 1) / 2, second, first);
    long length = 0;
    char *result = read_all(second, &length);
    if (0 != strcmp(expected, result)) {
        printf("result: %s, expected: %s\n", result, expected);
    }
    free(result);
}

int main() {
    {
        int array[] = {1};
        foo(array, " 1", sizeof(array) / sizeof(array[0]));
    }
    {
        int array[] = {1, 2};
        foo(array, "2  1", sizeof(array) / sizeof(array[0]));
    }
    {
        int array[] = {1, 2, 3};
        foo(array, "2  1 3", sizeof(array) / sizeof(array[0]));
    }
    {
        int array[] = {1, 2, 3, 4};
        foo(array, "2 4  1 3", sizeof(array) / sizeof(array[0]));
    }
    {
        int array[20] = {0};
        for (int i = 0; i < sizeof(array) / sizeof(array[0]); i++) {
            array[i] = i;
        }
        foo(array,
            "1 3 5 7 9 11 13 15 17 19  0 2 4 6 8 10 12 14 16 18",
            sizeof(array) / sizeof(array[0]));
    }

跳转到最佳答案楼层

赚小钱

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void write_2_files(int *nums, int count, FILE *first, FILE *second) {
    for (int i = 0; i < count; i++) {
        if (0 == (i & 1)) {
            fprintf(first, "%d ", nums[i]);
        } else {
            fprintf(second, "%d ", nums[i]);
        }
    }
}

char *read_all(FILE *f, long *length) {
    fseek(f, 0L, SEEK_END);
    *length = ftell(f);
    fseek(f, 0L, SEEK_SET);
    char *result = (char *) malloc(sizeof(char) * (*length + 1));
    memset(result, 0, sizeof(char) * (*length + 1));
    fread(result, sizeof(char), *length, f);
    return result;
}

char *read_ints(int count, FILE *from) {
    long length = 0;
    char *buffer = read_all(from, &length);
    int begin = 0, end = 0;
    for (begin = 0; begin < length; begin++) {
        char curr = buffer[begin];
        if (curr >= '0' && curr <= '9') {
            break;
        }
    }
    int found = 0;
    for (int i = begin + 1; i < length; i++) {
        char prev = buffer[i - 1];
        char curr = buffer[i];
        if (curr == ' ' && prev >= '0' && prev <= '9') {
            found += 1;
        }
        if (found >= count) {
            end = i;
            break;
        }
    }
    buffer[end] = '\0';
    char *result = strdup(buffer + begin);
    buffer[end] = ' ';
    free(buffer);
    return result;
}


void read_and_append_ints(int count, FILE *to, FILE *from) {
    char *buffer = read_ints(count, from);
    fprintf(to, " %s", buffer);
    free(buffer);
}

void foo(int *nums, const char *expected, int count) {
    FILE *first = fopen("f1.dat", "w+");
    FILE *second = fopen("f2.dat", "w+");
    write_2_files(nums, count, first, second);
    read_and_append_ints((count + 1) / 2, second, first);
    long length = 0;
    char *result = read_all(second, &length);
    if (0 != strcmp(expected, result)) {
        printf("result: %s, expected: %s\n", result, expected);
    }
    free(result);
}

int main() {
    {
        int array[] = {1};
        foo(array, " 1", sizeof(array) / sizeof(array[0]));
    }
    {
        int array[] = {1, 2};
        foo(array, "2  1", sizeof(array) / sizeof(array[0]));
    }
    {
        int array[] = {1, 2, 3};
        foo(array, "2  1 3", sizeof(array) / sizeof(array[0]));
    }
    {
        int array[] = {1, 2, 3, 4};
        foo(array, "2 4  1 3", sizeof(array) / sizeof(array[0]));
    }
    {
        int array[20] = {0};
        for (int i = 0; i < sizeof(array) / sizeof(array[0]); i++) {
            array[i] = i;
        }
        foo(array,
            "1 3 5 7 9 11 13 15 17 19  0 2 4 6 8 10 12 14 16 18",
            sizeof(array) / sizeof(array[0]));
    }

优秀的Aurora

赚小钱 发表于 2020-5-29 02:00

感谢解答！但是不知道为什么我运行的时候有错误C:\Users\lenovo\Desktop

优秀的Aurora

优秀的Aurora 发表于 2020-5-29 12:36
感谢解答！但是不知道为什么我运行的时候有错误

'strdup': The POSIX name for this item is deprecated. Instead, use the ISO C and C++ conformant name: _strdup. See online help for details.       

'fopen': This function or variable may be unsafe. Consider using fopen_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.

赚小钱

优秀的Aurora 发表于 2020-5-29 12:38
'strdup': The POSIX name for this item is deprecated. Instead, use the ISO C and C++ conformant na ...

把你的报错信息扔到 google translate 或者 有道词典。