Trying to do cipher decryption using C

[Aztec]

Hi, I'm trying to decrypt a ".txt" file using C language (cipher method). I keep getting loads of errors during compiling. Can someone please help me? Thanks! 

Code:

#include<stdio.h>
#include<stdlib.h>
#define MAX_SIZE 256 

int main(int argc, char *argv[])
{

*argv=[1], argv=[2]);
FILE *in_file, out_file;

in_file= fopen(argv[1], "r");
out_file= fopen(argv[2], "w");

void counter()

    char str[MAX_SIZE];
    int i, len;
    int freq[26];

    gets(%i);

    len = strlen(str);

    for(i=0; i<26; i++)
    {
        freq = 0;
    }

    for(i=0; i<len; i++)
    {

        if(str>='a' && str<='z')
        {
            freq[str - 97]++;
        }
        else if(str>='A' && str<='Z')
        {
            freq[str - 65]++;
        }
    }

char data[50], temp;
int key, count;

void shuttleSort(int a[], int n) {
    int i = 1, j;
    int temp;
    while (i < n) {
        j = i - 1;
        while (j >= 0) {
            if (a[j] > a[j + 1]) {
                temp = a[j];
                a[j] = a[j + 1];
                a[j + 1] = temp;
                j--;
            } else {
                break;
            }
        }
        i++;
    }
    printf("\n");
    printf("\nThe sorted array elements are given below\n");
    for (i = 0; i < n; i++) {
        printf("a[%d]=%d ", i, a);
    }
}
 void shuttle sort
    int i, n = 6;
    int a[] = {15, 8, 17, 12, 38, 19};
    printf("\n:: Shuttle Sort ::\n");
    printf("\nInput array elements\n");
    for (i = 0; i < n; i++) {
        printf("a[%d]=%d ", i, a);
    }

void caesar_cipher_decryption()
{
      for(count = 0; data[count] != '\0'; count++)
      {
            temp = data[count];
            if(temp >= 'a' && temp <= 'z')
            {
                  temp = temp - key;
                  if(temp < 'a')
                  {
                        temp = temp + 'z' - 'a' + 1;
                  }
                  data[count] = temp;
            }
            else if(temp >= 'A' && temp <= 'Z')
            {
                  temp = temp - key;
                  if(temp < 'A')
                  {
                        temp = temp + 'Z' - 'A' + 1;
                  }
                  data[count] = temp;
            }
      }
      printf("\nDecrypted Message:\t%s\n", data);
}

[Mira Yurizaki]

Here's the immediate problems I see

• main doesn't have an end curly brace, or it does and it's encapsulating everything, which in the context of the rest of the source, is not allowed because nested function definitions aren't allowed in C.
• Closing parenthesis at the statement *argv=[1], argv=[2]);
  • Also this statement makes no sense.
• Functions counter and shuttle_sort don't have curly braces encapsulating the function
  • There's also another function called shuttleSort... so which one are you using?
• Declaration of data[50], temp, key, and count are ambiguous in terms of scope. Are they global to the source, local to a function, what?
• Not checking to make sure argv is of correct size before proceeding (what if I call the program with no arguments?)

I'm not going to re-write the source for you, but maybe someone who's more generous than me will.

Edited December 6, 2017 by M.Yurizaki

[Aztec]

6 hours ago, M.Yurizaki said:

Here's the immediate problems I see

• main doesn't have an end curly brace, or it does and it's encapsulating everything, which in the context of the rest of the source, is not allowed because nested function definitions aren't allowed in C.
• Closing parenthesis at the statement *argv=[1], argv=[2]);
  • Also this statement makes no sense.
• Functions counter and shuttle_sort don't have curly braces encapsulating the function
  • There's also another function called shuttleSort... so which one are you using?
• Declaration of data[50], temp, key, and count are ambiguous in terms of scope. Are they global to the source, local to a function, what?
• Not checking to make sure argv is of correct size before proceeding (what if I call the program with no arguments?)

I'm not going to re-write the source for you, but maybe someone who's more generous than me will.

Thank you. I've got a code that detects the letters and then one that shuttle sorts them and then the decrypt. I'm fairly new to C language as you can probs tell haha.