o.c

// cc -o o ./o.c && ./o > o.py
#include <stdio.h>
#include <string.h>

int main()
{
    char buf[256];
    const char *self = "# python ./o.py > o.c\nself = \"?\"\nfor x in self.split(chr(124))[1]:\n    if ord(x) == 63:\n        for y in self:\n            if y == '\\n': print(\"\\\\n\", end='')\n            elif y == '\"': print(\"\\\\\\\"\", end='')\n            elif y == '\\\\': print(\"\\\\\\\\\", end='')\n            else: print(f\"{y}\", end='')\n    else:\n        print(x, end='')\n|// cc -o o ./o.c && ./o > o.py\n#include <stdio.h>\n#include <string.h>\n\nint main()\n{\n    char buf[256];\n    const char *self = \"?\";\n    int n = strlen(self);\n    for (int i = 0; self[i] != 124; ++i) {\n        if (self[i] == 63) {\n            for (int j = 0; j < n; ++j) {\n                switch (self[j]) {\n                case '\\n':  printf(\"\\\\n\");  break;\n                case '\"':   printf(\"\\\\\\\"\"); break;\n                case '\\\\':  printf(\"\\\\\\\\\"); break;\n                default: printf(\"%c\", self[j]);\n                }\n            }\n        } else {\n            printf(\"%c\", self[i]);\n        }\n    }\n    return 0;\n}\n";
    int n = strlen(self);
    for (int i = 0; self[i] != 124; ++i) {
        if (self[i] == 63) {
            for (int j = 0; j < n; ++j) {
                switch (self[j]) {
                case '\n':  printf("\\n");  break;
                case '"':   printf("\\\""); break;
                case '\\':  printf("\\\\"); break;
                default: printf("%c", self[j]);
                }
            }
        } else {
            printf("%c", self[i]);
        }
    }
    return 0;
}

q.c

// cc -o q ./q.c && ./q < q.q > q1.c
#include <stdio.h>
#include <string.h>

int main()
{
    char buf[256];
    const char *self = "// cc -o q ./q.c && ./q < q.q > q1.c\n#include <stdio.h>\n#include <string.h>\n\nint main()\n{\n    char buf[256];\n    const char *self = \"?\";\n    for (;;) {\n        char *s = fgets(buf, sizeof(buf), stdin);\n        if (s == NULL) break;\n        while (*s) {\n            if (*s == 'q') {\n                int n = strlen(self);\n                for (int i = 0; i < n; ++i) {\n                    if (self[i] == 63) {\n                        for (int j = 0; j < n; ++j) {\n                            switch (self[j]) {\n                            case '\\n':  printf(\"\\\\n\");  break;\n                            case '\"':   printf(\"\\\\\\\"\"); break;\n                            case '\\\\':  printf(\"\\\\\\\\\"); break;\n                            default: printf(\"%c\", self[j]);\n                            }\n                        }\n                    } else {\n                        printf(\"%c\", self[i]);\n                    }\n                }\n            }\n            s += 1;\n        }\n    }\n    fclose(fopen(\"some-random-file.txt\", \"wb\"));\n    return 0;\n}\n";
    for (;;) {
        char *s = fgets(buf, sizeof(buf), stdin);
        if (s == NULL) break;
        while (*s) {
            if (*s == 'q') {
                int n = strlen(self);
                for (int i = 0; i < n; ++i) {
                    if (self[i] == 63) {
                        for (int j = 0; j < n; ++j) {
                            switch (self[j]) {
                            case '\n':  printf("\\n");  break;
                            case '"':   printf("\\\""); break;
                            case '\\':  printf("\\\\"); break;
                            default: printf("%c", self[j]);
                            }
                        }
                    } else {
                        printf("%c", self[i]);
                    }
                }
            }
            s += 1;
        }
    }
    fclose(fopen("some-random-file.txt", "wb"));
    return 0;
}

q.q

q