cipher

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

void writeFile(char *fPath, char *inputString, int *cc, char *fflag) {
    FILE *tFile;
    tFile = fopen(fPath, "r");
    if (tFile) {
        fclose(tFile);
        tFile = fopen(fPath, fflag);
        fprintf(tFile, "%s", inputString);
    } else {
        *cc = 1;
        printf("n/a\n");
    }
    if (tFile) fclose(tFile);
}

void getCountBytesInFile(char *fPath, long *fLength, int *er) {
    FILE * tFile;
    tFile = fopen(fPath, "rb");
    if (!tFile) {
        *er = 1;
    } else {
        fseek(tFile, 0, SEEK_END);
        *fLength = ftell(tFile);
        fclose(tFile);
    }
}

void read_n_Print_File(char *fPath, long *fLength) {
    if (fLength != 0) {
        FILE *tFile;
        tFile = fopen(fPath, "rb");
        printf("f");
        if (tFile) {
            int symbol;
            while ( (symbol = fgetc(tFile) ) != EOF ) {
                putchar(symbol);
            }
            printf("\n");
        }
        if (tFile) fclose(tFile);
    } else {
        printf("n/a");
    }
}

char *getString() {
    char *fPath = NULL;
    char c;
    int len = 0;
    fPath = (char*)malloc(sizeof(char));
    while ((c = getchar()) != '\n') {
        fPath[len] = c;
        len++;
        char *tmp = (char*)realloc(fPath, len);
        if (NULL != tmp) {
            fPath = tmp;
        }
    }
    fPath[len] = '\0';
    return fPath;
}

char *get_filename_ext(const char *filename) {
    char *dot = strrchr(filename, '.');
    if (!dot || dot == filename) return "";
    return dot + 1;
}

void toCaesar(char *concat, int shift) {
    FILE *tFile;
    char aOut[100];
    tFile = fopen(concat, "r");
    int symbol;
    int i = 0; int cc = 0;
    while ( (symbol = fgetc(tFile) ) != EOF ) {
        if (symbol >= 65 && symbol <= 90) {
            symbol = symbol + (shift % 26);
            if (symbol > 90) symbol = 65 + (symbol - 90) - 1;
            aOut[i] = (char)(symbol);
        } else if (symbol >= 97 && symbol <= 122) {
            symbol = symbol + (shift % 26);
            if (symbol > 122) symbol = 97 + (symbol - 122) - 1;
            aOut[i] = (char)(symbol);
        } else if (symbol >= 33 && symbol <= 64) {
            symbol = symbol + (shift % 32);
            if (symbol > 64) symbol = 33 + (symbol - 64) - 1;
            aOut[i] = (char)(symbol);
        } else if (symbol >= 123 && symbol <= 126) {
            symbol = symbol + (shift % 4);
            if (symbol > 126) symbol = 123 + (symbol - 126) - 1;
            aOut[i] = (char)(symbol);
        } else if (symbol >= 192 && symbol <= 223) {
            symbol = symbol + (shift % 32);
            if (symbol > 223) symbol = 192 + (symbol - 223) - 1;
            aOut[i] = (char)(symbol);
        } else if (symbol >= 224 && symbol <= 255) {
            symbol = symbol + (shift % 32);
            if (symbol > 255) symbol = 224 + (symbol - 255) - 1;
            aOut[i] = (char)(symbol);
        } else {
            aOut[i] = (char)(symbol);
        }
        i++;
    }
    fclose(tFile);
    char *fflag = "w";
    writeFile(concat, aOut, &cc, fflag);
}

void quest3() {
    DIR *dir;
    struct dirent *de;
    char *fPath = NULL;

    fPath = getString();
    dir = opendir(fPath);
    if (dir) {
        int shift;
        scanf("%d", &shift);
        if (getchar() != '\n') {
            printf("n/a\n");
        } else {
            while (dir) {
                de = readdir(dir);
                if (!de) break;
                char *fName = de->d_name;
                char *ext = get_filename_ext(fName);
                char concat[512];
                snprintf(concat, sizeof concat, "%s/%s", fPath, fName);
                if (strcmp(ext, "h") == 0) {
                    FILE *tFile;
                    tFile = fopen(concat, "w");
                    fclose(tFile);
                } else if (strcmp(ext, "c") == 0) {
                    toCaesar(concat, shift);
                }
            }
        }
    closedir(dir);
    } else {
        printf("n/a\n");
    }
    if (NULL != fPath) free(fPath);
}

int main() {
    char *fPath = NULL;
    char *fTemp = NULL;
    char *inputString = NULL;
    int er = 0;
    int n;
    char charTest;
    int menu_item = 0;

    while (menu_item != -1) {
        clearerr(stdin);
        if ((scanf("%d%c", &n, &charTest) == 2) &&
            (n == -1) && charTest == '\n') {
            menu_item = -1;
        } else if (n == 1 && charTest == '\n') {
            fPath = getString();
            long fLength = 0;
            getCountBytesInFile(fPath, &fLength, &er);
            if ((strlen(fPath) == 0) || (er == 1) || fLength == 0) {
                printf("n/a\n");
                er = 0;
            } else {
                read_n_Print_File(fPath, &fLength);
            }
            fTemp = fPath;
            if (NULL != fPath) free(fPath);
        } else if (n == 2 && charTest == '\n') {
            inputString = getString();
            int cc = 0;
            if (fTemp) {
                char *fflag = "a";
                writeFile(fTemp, inputString, &cc, fflag);
            }
            if (inputString) {
                if (fTemp) {
                    long fLength = 0;
                    getCountBytesInFile(fTemp, &fLength, &er);
                    read_n_Print_File(fTemp, &fLength);
                } else if (cc != 1) {
                    printf("n/a\n");
                }
            }
            if (NULL != inputString) free(inputString);
        } else if (n == 3 && charTest == '\n') {
            quest3();
        } else if (EOF) {
            if (NULL != inputString) free(inputString);
            clearerr(stdin);
            fflush(NULL);
        } else {
            printf("n/a\n");
            fflush(NULL);
            if (NULL != fTemp) free(fTemp);
        }
    }
    return 0;
}