Garbage characters being store in the array - c++

Question

I'm trying to copy data from an array of character that send from main to another one in my local function and I always see garbage characters even though I've add '\0' at the end of the string.
Here is my partial of the code.
for (int i = 0; i < strlen(main) ; i++){
if (main[i] != ';'){
local[i] = main[i]; // Copy the characters until `;` isn't found
} else {
local[i] = '\0' ; // If `;` found, null terminate the copied destination.
break;
}
}
so basically the data that being send from main for example like this
look;can;you;see;me
My Local-----> 'look??y??>c?Lw?T?w??>c?2+a?'
Actual data in main---> 'look'
As you can see from the above example I'm trying to get only the first word and I always get garbage I don't know why?
EDIT:
This is the almost the whole function which 100% sure that is causing me the problem.
void myFunction(char main[ ]){
for (int i = 0; i < strlen(main) ; i++){
if (main[i] != ';'){
local[i] = main[i]; // Copy the characters until `;` isn't found
} else {
local[i] = '\0' ; // If `;` found, null terminate the copied destination.
break;
}
}
if(main[i] != '\0'){
int col = 0, row = 0;
do {
if(main[i] == ';' || main[i] == '\0') {
sending[row++][col] = '\0';
col = 0;
} else {
sending[row][col++] = main[i];
}
} while(main[i++] != '\0');
}
}

Answer 1

You are forgetting to take care of zero terminating the string if the ; is not found. A simple fix is tweaking your for loop so it also sees the \0 in main:
for (int i = 0; i <= strlen(main); i++) {

Answer 2

The standard library handles this for you. Using strchr and strncpy:
size_t length = std::strlen(main);
const char* current_pos = main;
for (int i = 0; ; ++i) {
size_t chars_remaining = length - std::distance(main, current_pos);
const char* end_of_field = std::strchr(current_pos, ';');
if (end_of_field == NULL) {
std::strncpy(local[i], current_pos, chars_remaining + 1);
// we're at the end of the input
break;
}
else {
size_t field_length = std::distance(current_pos, end_of_field);
std::strncpy(local[i], current_pos, field_length);
// don't forget to NUL-terminate the string
local[i][field_length] = '\0';
// go to next character for the next iteration through loop
current_pos = end_of_field + 1;
}
}
Personally, I prefer std::find and std::copy (from <algorithm>):
size_t length = std::strlen(main);
const char* current_pos = main;
for (int i = 0; ; ++i) {
size_t chars_remaining = length - std::distance(main, current_pos);
const char* end_of_field = std::find(current_pos, current_pos + chars_remaining, ';');
char* output_end = std::copy(current_pos, end_of_field, local[i]);
// don't forget to NUL-terminate the string
*output_end = '\0';
// if we're at the end of main, then we're done;
// we're at the end if we're on a NUL character
if (*end_of_field == '\0')
break;
// go to next character for the next iteration through loop
current_pos = end_of_field + 1;
}
Not the prettiest code I've ever written, but that's largely due to using C-style strings and pointer arithmetic, which don't look avoidable given the original question. Additionally, I haven't put in the needed checks for overflow. It's easy enough to do that, but it's even easier to use std::vector<std::string> and have the standard library worry about that for you.