/*
* var: char* & const char*
* return: char*
* Copies the characters from source into destination.
*/
char* new_strcpy(char* destination, const char* source)
{
int length = (int) new_strlen(source);
int i;
for(i = 0 ; i < length + 1 ; i++) //adds each character from source to the destination
destination[i] = source[i];
return destination; //returns the new copy
}
/*
* var: const char* & int
* return: char*
* Returns a pointer to the first occurrence of character (converted to a char) in string or a NULL pointer if character cannot be found.
*/
char* new_strchr(const char* string, int character)
{
int i;
int length = new_strlen(string);
for(i = 0 ; i < length ; i++) //goes through the length of the string
if(string[i] == (char) character)
return (char*) &string[i]; //if it reaches a character that matches the character provided, it returns the first instance of the character.
return NULL; //otherwise returns null
}
/*
* var: char* & const char* & size_t
* return: char*
* Adds the string contained in source to the end of the string contained in destination, but adding a maximum of n characters.
*/
char* new_strncat(char* destination, const char* source, size_t n)
{
size_t length = new_strlen(destination);
size_t i;
for (i = 0 ; i < n && source[i] != '\0' ; i++) //goes through the source until null character or n number of times
destination[length + i] = source[i]; //adds the character in source to the end of destination
destination[length + i] = '\0'; //adds a null character at the very end
return destination;
}
/*
* var: const char* & const char*
* return: char*
* Returns a pointer to the first occurrence of the string contained in needle in haystack or a NULL pointer if needle cannot be found.
*/
char* new_strstr(const char* haystack, const char* needle)
{
int i;
for(i = 0 ; i < new_strlen(haystack) ; i++) //goes through the length of the haystack
{
int j = 0;
if(haystack[i] == needle[j]) //if it finds the first character in needle
{
while(haystack[i+j] == needle[j]) //loop through the and check to see if the next characters match.
j++;
if(needle[j] == '\0') //if the null character in needle is reached, that means we have a match
return (char*) &haystack[i]; //return the location in haystack where the needle is
}
}
return NULL; //otherwise return null
}
int test_strlen(char* str, int log)
{
int return1, return2;
return1 = strlen(str);
return2 = new_strlen(str);
if(log)
{
printf("strlen: str: %s return: %d\n",
str, return1);
printf("new_strlen: str: %s return: %d\n",
str, return2);
}
return return1==return2;
}
