Iterate Over Char Array Elements in C - c

Question

This code is supposed to take a user's input and convert it to binary. The input is grouped into an integer array to store character codes and/or adjacent digits, then each item in the integer array is converted to binary. When the user types "c357", "c" should be converted to 99, then converted to binary. Then, "357" should be converted to binary as well. In the main() function, strlen(convert) does not accurately represent the number of items in array convert, thus only iterating over the first array item.
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <unistd.h>
#include <string.h>
#define EIGHT_BITS 255
#define SIXTEEN_BITS 65535
#define THIRTY_TWO_BITS 4294967295UL
// DETERMINE NUMBER OF BITS TO OUTPUT
int getBitLength(unsigned long d) {
int l;
if (d <= EIGHT_BITS) {
l = 8;
}
else if (d > EIGHT_BITS && d <= SIXTEEN_BITS) {
l = 16;
}
else if (d > SIXTEEN_BITS && d <= THIRTY_TWO_BITS) {
l = 32;
}
return l;
}
// CONVERT INPUT TO BINARY VALUE
char* convertToBinary(unsigned long int decimal) {
int l = getBitLength(decimal);
static char b[33];
char bin[33];
int i, j, k = 0, r;
b[33] = '\0';
bin[33] = '\0';
printf("Bits................ %ld\n", l);
// creates array
for (i = 0; i < l; i++) {
r = decimal % 2;
decimal /= 2;
b[i] = r;
}
// reverses array for binary value
for (j = l - 1; j >= 0; j--) {
bin[k] = b[j];
strncpy(&bin[k], &b[j], l);
snprintf(&bin[k], l, "%d", b[j]);
k++;
}
printf("Binary Value: %s\n", bin);
return bin;
}
unsigned long int* numbersToConvert(char* input) {
const int MAX_INPUT = 20;
int i, k = 0, z = 0;
char numbers[MAX_INPUT];
unsigned long int *toConvert = malloc(MAX_INPUT * sizeof(int));
numbers[MAX_INPUT] = '\0';
for (i = 0; i < strlen(input); i++) {
if (isdigit(input[i])) {
numbers[z] = input[i];
if (!isdigit(input[i + 1])) {
toConvert[k] = strtol(numbers, NULL, 10);
printf("----- %ld -----\n", toConvert[k]);
z = 0;
}
else {
z++;
}
}
else {
printf("----- %c -----\n", input[i]);
printf("Character Code: %d\n", input[i]);
toConvert[k] = (unsigned long int) input[i];
}
k++;
}
return toConvert;
}
int main(void) {
const int MAX_INPUT = 20;
int i, p;
char input[MAX_INPUT];
unsigned long int* convert;
printf("------- Input --------\n");
scanf("%s", input);
input[MAX_INPUT] = '\0';
// PRINT INPUT AND SIZE
printf("\nInput: %s\n", input);
convert = numbersToConvert(input);
convert[MAX_INPUT] = '\0';
printf("strlen: %ld\n", strlen(convert));
for (i = 0; i < strlen(convert); i++) {
printf("num array: %ld\n", convert[i]);
convertToBinary(convert[i]);
}
return 0;
}
I have attempted to null terminate each string to prevent undefined behavior. I am unsure if certain variables, if any, are meant to be static.

Answer 1

It is hard to read your code.
Here you have something working (converting the number to binary):
static char *reverse(char *str)
{
char *end = str + strlen(str) - 1;
char *saved = str;
int ch;
while(end > str)
{
ch = *end;
*end-- = *str;
*str++ = ch;
}
return saved;
}
char *tostr(char *buff, unsigned long long val)
{
if(buff)
{
char *cpos = buff;
while(val)
{
*cpos++ = (val & 1) + '0';
val >>= 1;
}
*cpos = 0;
reverse(buff);
}
return buff;
}
int main()
{
char buff[128];
printf("%s\n", tostr(buff, 128));
}
https://godbolt.org/z/6sRC4C