Pointers and Functions with Arrays

[halamaker]

So, I think I've got this mostly figured out but I'm receiving two error codes when I attempt to compile this code. The assignment specifies that we are not to use any functions from the cstring library. I am unsure about how to go about the code for the last two functions to append str2 and str3 to str1 but I gave it a shot...the error messages I am receiving are:

1> error LNK2019: unresolved external symbol "int __cdecl stringLength1(char *)" (?stringLength1@@YAHPAD@Z) referenced in function _main
1> fatal error LNK1120: 1 unresolved externals

Any direction would be much appreciated, thanks so much!

 #include <iostream>
using namespace std;

// Implement the following function prototypes
int   stringLength1 (char *str);
int   stringLength2 (char *str);
char* stringCopy1 (char *str1, const char *str2);
char* stringCopy2 (char *str1, const char *str3);
char* stringCat1 (char *str1, const char *str2);
char* stringCat2 (char *str1, const char *str3);

// Use the following driver to test implementations:
int main()
{
	char  str1[20];
	char* str2 = "Forrest";
	char* str3 = "Run";
  
	// Test stringLength functions
   
	cout << "stringLength1 (" << str2 << "): "
		<< stringLength1 (str2) << endl;
	cout << "stringLength2 (" << str3 << "): "
		<< stringLength2 (str3) << endl;

	// Test stringCopy functions
   
	cout << "stringCopy1 (str1, " << str2 << "): "
		<< stringCopy1 (str1, str2) << endl;
	cout << "stringCopy2 (str1, " << str3 << "): "
		<< stringCopy2 (str1, str3) << endl;
 
	// Test stringCat functions
   
	cout << "stringCat1 (str1, " << str2 << "): "
		<< stringCat1 (str1, str2) << endl;
	cout << "stringCat2 (str1, " << str3 << "): "
		<< stringCat2 (str1, str3) << endl;
 
	return 0; 
} // end main

int stringLength1(const char* str)
{
	int counter = 0;
		
		while(str[counter] != '\0')
		{
			counter++;
		}
	
	return counter;
}

int   stringLength2 (char *str)
{
	int counter = 0;
		
		while(str[counter] != '\0')
		{
			counter++;
		}
	
	return counter;
}

char* stringCopy1 (char *str1, const char *str2)
{
	*str1 = *str2;

	return str1;
}

char* stringCopy2 (char *str1, const char *str3)
{
	*str1 = *str3;

	return str1;
}

char* stringCat1 (char *str1, const char *str2)
{
	int size = stringLength1(str2);
	char *null = new char[stringLength1(str2) + 1];

	null[stringLength1(str2)] = size;
	null[stringLength1(str2) + 1] = '\0';
  
	return null;
}

char* stringCat2 (char *str1, const char *str3)
{
	int size = stringLength1(str3);
	char *null = new char[stringLength1(str3) + 1];

	null[stringLength1(str3)] = size;
	null[stringLength1(str3) + 1] = '\0';
  
	return null;
}

[norm b]

The stringLength1 function signatures don't match.

int   stringLength1 (char *str);
int stringLength1(const char* str)

[halamaker]

Oh lord ok, got that that was a total oversight on my part... well it compiles but now all I get is garbage back.... the out put I'm looking for is:

stringLength1 (Forrest): 7
stringLength2 (Run): 3
stringCopy1 (str1, Forrest): Forrest
stringCopy2 (str1, Run): Run
stringCat1 (str1, Forrest): RunForrest
stringCat2 (str1, Run): RunForrestRun

stringLenth1 and 2 return correctly but I get a bunch of nonsense for the remaining 4...

[halamaker]

Alrighty I've worked with it some and got the 2nd pair of functions to give me the correct output, but the final two functions break.

My code so far:

#include <iostream>
using namespace std;

// Implement the following function prototypes
int   stringLength1 (const char *str);
int   stringLength2 (const char *str);
char* stringCopy1 (char *str1, char *str2);
char* stringCopy2 (char *str1, char *str3);
char* stringCat1 (char *str1, char *str2);
char* stringCat2 (char *str1, char *str3);

// Use the following driver to test implementations:
int main()
{
	char  str1[20];
	char* str2 = "Forrest";
	char* str3 = "Run";
  
	// Test stringLength functions
   
	cout << "stringLength1 (" << str2 << "): "
		<< stringLength1 (str2) << endl;
	cout << "stringLength2 (" << str3 << "): "
		<< stringLength2 (str3) << endl;

	// Test stringCopy functions
   
	cout << "stringCopy1 (str1, " << str2 << "): "
		<< stringCopy1 (str1, str2) << endl;
	cout << "stringCopy2 (str1, " << str3 << "): "
		<< stringCopy2 (str1, str3) << endl;
 
	// Test stringCat functions
   
	cout << "stringCat1 (str1, " << str2 << "): "
		<< stringCat1 (str1, str2) << endl;
	cout << "stringCat2 (str1, " << str3 << "): "
		<< stringCat2 (str1, str3) << endl;
 
	system("pause");
	return 0; 
} // end main


//Determines the length of string str. The number of characters preceding the terminating null character is returned.
int stringLength1(const char* str)
{
	int counter = 0;
		
		while(str[counter] != '\0')
		{
			counter++;
		}
	
	return counter;
}

int   stringLength2 (const char *str)
{
	int counter = 0;
		
		while(str[counter] != '\0')
		{
			counter++;
		}
	
	return counter;
}

//Copies the string str2 into the character array str1. The value of str1 is returned.
char* stringCopy1 (char *str1, char *str2)
{
	str1 = str2;

	return str1;
}

char* stringCopy2 (char *str1, char *str3)
{
	str1 = str3;

 	return str1;
}

//Appends a copy of string str2 to string str1. The first character of str2 overwrites the terminating null character of str1. The value of str1 is returned.
char* stringCat1 (char *str1, char *str2)
{
	char *cat = '\0';
	
	*cat = *str1 + *str2;

	return cat;
}

char* stringCat2 (char *str1, char *str3)
{
	char *cat = '\0';
	
	*cat = *str1 + *str3;

	return cat;
}