[已解决]main函数的位置

南城转暖

main函数只能放在固定位置还是可以放在符合语法的任意位置。如果可以的话能不能举几个例子。ps：百度告诉我可以放在任意位置，但是我不知道怎么放！

最佳答案

月排行榜 / 总排行榜

人造人

2021-3-16 09:02:10

可以放在符合语法的任意位置，我比较喜欢放在最后面，这样可以省去声明函数

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>

size_t lines(const char *filename) {
    struct stat sb;
    if(lstat(filename, &sb) != 0) return 0;
    if(sb.st_size == 0) return 0;

    size_t count = 1;
    int fd = open(filename, O_RDONLY);
    char *buf = malloc(sb.st_size);
    read(fd, buf, sb.st_size);
    for(long i = 0; i < sb.st_size; ++i) {
        if(buf[i] == '\n') ++count;
    }
    free(buf);
    close(fd);
    return count;
}

const char *suffix(const char *filename) {
    return strrchr(filename, '.');
}

size_t count_lines(const char *path) {
    size_t count = 0;
    DIR *dirp = opendir(path);
    if(!dirp) return 0;

    struct dirent *de;
    char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    while((de = readdir(dirp))) {
        if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
        if(de->d_type == DT_DIR) {
            count += count_lines(de->d_name);
        }
        const char *s = suffix(de->d_name);
        if(!s || strcmp(s, ".c")) continue;
        count += lines(de->d_name);
    }
    chdir(cwd); free(cwd);
    closedir(dirp);
    return count;
}

int main(void) {
    printf("%lu\n", count_lines("../"));
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>

size_t lines(const char *filename);
const char *suffix(const char *filename);
size_t count_lines(const char *path);

int main(void) {
    printf("%lu\n", count_lines("../"));
    return 0;
}

size_t lines(const char *filename) {
    struct stat sb;
    if(lstat(filename, &sb) != 0) return 0;
    if(sb.st_size == 0) return 0;

    size_t count = 1;
    int fd = open(filename, O_RDONLY);
    char *buf = malloc(sb.st_size);
    read(fd, buf, sb.st_size);
    for(long i = 0; i < sb.st_size; ++i) {
        if(buf[i] == '\n') ++count;
    }
    free(buf);
    close(fd);
    return count;
}

const char *suffix(const char *filename) {
    return strrchr(filename, '.');
}

size_t count_lines(const char *path) {
    size_t count = 0;
    DIR *dirp = opendir(path);
    if(!dirp) return 0;

    struct dirent *de;
    char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    while((de = readdir(dirp))) {
        if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
        if(de->d_type == DT_DIR) {
            count += count_lines(de->d_name);
        }
        const char *s = suffix(de->d_name);
        if(!s || strcmp(s, ".c")) continue;
        count += lines(de->d_name);
    }
    chdir(cwd); free(cwd);
    closedir(dirp);
    return count;
}

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>

size_t lines(const char *filename) {
    struct stat sb;
    if(lstat(filename, &sb) != 0) return 0;
    if(sb.st_size == 0) return 0;

    size_t count = 1;
    int fd = open(filename, O_RDONLY);
    char *buf = malloc(sb.st_size);
    read(fd, buf, sb.st_size);
    for(long i = 0; i < sb.st_size; ++i) {
        if(buf[i] == '\n') ++count;
    }
    free(buf);
    close(fd);
    return count;
}

const char *suffix(const char *filename);
size_t count_lines(const char *path);

int main(void) {
    printf("%lu\n", count_lines("../"));
    return 0;
}

const char *suffix(const char *filename) {
    return strrchr(filename, '.');
}

size_t count_lines(const char *path) {
    size_t count = 0;
    DIR *dirp = opendir(path);
    if(!dirp) return 0;

    struct dirent *de;
    char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    while((de = readdir(dirp))) {
        if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
        if(de->d_type == DT_DIR) {
            count += count_lines(de->d_name);
        }
        const char *s = suffix(de->d_name);
        if(!s || strcmp(s, ".c")) continue;
        count += lines(de->d_name);
    }
    chdir(cwd); free(cwd);
    closedir(dirp);
    return count;
}

跳转到最佳答案楼层

人造人

可以放在符合语法的任意位置，我比较喜欢放在最后面，这样可以省去声明函数

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>

size_t lines(const char *filename) {
    struct stat sb;
    if(lstat(filename, &sb) != 0) return 0;
    if(sb.st_size == 0) return 0;

    size_t count = 1;
    int fd = open(filename, O_RDONLY);
    char *buf = malloc(sb.st_size);
    read(fd, buf, sb.st_size);
    for(long i = 0; i < sb.st_size; ++i) {
        if(buf[i] == '\n') ++count;
    }
    free(buf);
    close(fd);
    return count;
}

const char *suffix(const char *filename) {
    return strrchr(filename, '.');
}

size_t count_lines(const char *path) {
    size_t count = 0;
    DIR *dirp = opendir(path);
    if(!dirp) return 0;

    struct dirent *de;
    char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    while((de = readdir(dirp))) {
        if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
        if(de->d_type == DT_DIR) {
            count += count_lines(de->d_name);
        }
        const char *s = suffix(de->d_name);
        if(!s || strcmp(s, ".c")) continue;
        count += lines(de->d_name);
    }
    chdir(cwd); free(cwd);
    closedir(dirp);
    return count;
}

int main(void) {
    printf("%lu\n", count_lines("../"));
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>

size_t lines(const char *filename);
const char *suffix(const char *filename);
size_t count_lines(const char *path);

int main(void) {
    printf("%lu\n", count_lines("../"));
    return 0;
}

size_t lines(const char *filename) {
    struct stat sb;
    if(lstat(filename, &sb) != 0) return 0;
    if(sb.st_size == 0) return 0;

    size_t count = 1;
    int fd = open(filename, O_RDONLY);
    char *buf = malloc(sb.st_size);
    read(fd, buf, sb.st_size);
    for(long i = 0; i < sb.st_size; ++i) {
        if(buf[i] == '\n') ++count;
    }
    free(buf);
    close(fd);
    return count;
}

const char *suffix(const char *filename) {
    return strrchr(filename, '.');
}

size_t count_lines(const char *path) {
    size_t count = 0;
    DIR *dirp = opendir(path);
    if(!dirp) return 0;

    struct dirent *de;
    char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    while((de = readdir(dirp))) {
        if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
        if(de->d_type == DT_DIR) {
            count += count_lines(de->d_name);
        }
        const char *s = suffix(de->d_name);
        if(!s || strcmp(s, ".c")) continue;
        count += lines(de->d_name);
    }
    chdir(cwd); free(cwd);
    closedir(dirp);
    return count;
}

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <dirent.h>
#include <string.h>

size_t lines(const char *filename) {
    struct stat sb;
    if(lstat(filename, &sb) != 0) return 0;
    if(sb.st_size == 0) return 0;

    size_t count = 1;
    int fd = open(filename, O_RDONLY);
    char *buf = malloc(sb.st_size);
    read(fd, buf, sb.st_size);
    for(long i = 0; i < sb.st_size; ++i) {
        if(buf[i] == '\n') ++count;
    }
    free(buf);
    close(fd);
    return count;
}

const char *suffix(const char *filename);
size_t count_lines(const char *path);

int main(void) {
    printf("%lu\n", count_lines("../"));
    return 0;
}

const char *suffix(const char *filename) {
    return strrchr(filename, '.');
}

size_t count_lines(const char *path) {
    size_t count = 0;
    DIR *dirp = opendir(path);
    if(!dirp) return 0;

    struct dirent *de;
    char *cwd = malloc(PATH_MAX); getcwd(cwd, PATH_MAX); chdir(path);
    while((de = readdir(dirp))) {
        if(!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) continue;
        if(de->d_type == DT_DIR) {
            count += count_lines(de->d_name);
        }
        const char *s = suffix(de->d_name);
        if(!s || strcmp(s, ".c")) continue;
        count += lines(de->d_name);
    }
    chdir(cwd); free(cwd);
    closedir(dirp);
    return count;
}

chxchxkkk

意思就是你不用把main函数放在程序的第一行，在第任意行都可以

南城转暖

chxchxkkk 发表于 2021-3-16 09:23
意思就是你不用把main函数放在程序的第一行，在第任意行都可以

不可以放结尾吗？或者在其他位置吗

wp231957

人造人 发表于 2021-3-16 09:42
可以放在符合语法的任意位置，我比较喜欢放在最后面，这样可以省去声明函数

搭车问一下，您是否用过vscode+gcc
这个组合，我现在在vscode里无法编译

南城转暖

wp231957 发表于 2021-3-16 10:00
搭车问一下，您是否用过vscode+gcc
这个组合，我现在在vscode里无法编译

什么意思呢？如何无法编辑？

人造人

wp231957 发表于 2021-3-16 10:00
搭车问一下，您是否用过vscode+gcc
这个组合，我现在在vscode里无法编译

之前弄过，详细说明你的问题
qq: 1440332527