String Handling Library

John T. Rine
Discrete Structures
Fall 2011

My library is available at:
http://lab46.corning-cc.edu/~jr018429/Library.zip

The Discrete group to which I belong has a Wiki page is located at:
http://lab46.corning-cc.edu/notes/discrete/setman

My library is composed of the following functions:

int cntChars(char *)
The function cntChars takes as its parameter a character pointer (the base address of a character array, a string, and returns the number of characters in the string up to the maximum size of an integer).
Example code:

//John T. Rine
//September 23, 2011
 
#include<stdio.h>
 
#include "jr.h"
 
int main(int argc, char **argv)
{
	char myString[]="John Rine";
	printf("%s\n", myString);
	printf("The number of character in my string is %d\n", cntChars(myString));
 
	return 0;
}

Output:

lab46:~/Library$ ./cntChars
Please enter a string between 1 and 250 characters long
John Rine
The number of capital characters in your string is: 2
The number of lower case characters in your string is: 6
The number of number characters in your string is: 2
lab46:~/Library$

char *append(char, char *)
The function append takes as function parameters a character to append, and a character pointer (the base address of a character array, a string). append returns a pointer to a string which is composed of the original string with the character supplied as a parameter appended to the end.
Example code:

//John T. Rine
//September 23, 2011
 
#include<stdio.h>
#include<stdlib.h>
#include "jr.h"
 
int main(int argc, char **argv)
{
	char temp;
	char *ptrChar;
 
	if (argc == 1) printf("Should be at least one command line argument supplied after the file name\n");
	else
	{
		//only appends to first argument after filename
		printf("Enter a character to append to the string supplied on the command line\n");
		temp = getchar();
		printf("%s\n", ptrChar = append(temp, *(argv + 1)));
		free(ptrChar);
	}
 
	return(0);
}

Output:

lab46:~/Library$ ./appendL Joh
Enter a character to append to the string supplied on the command line
n
John
lab46:~/Library$

char *prepend(char, char *)
The function prepend takes as function parameters a character to prepend, and a character pointer (the base address of a character array, a string). prepend returns a pointer to a string which is composed of the original string with the character supplied as a parameter prepended to the beginning of the string.
Example code:

//John T. Rine
//September 23, 2011
 
#include<stdio.h>
#include<stdlib.h>
#include "jr.h"
 
 
int main(int argc, char **argv)
{
	char temp;
	char *ptrChar;
 
	if (argc == 1) printf("Should be at least one command line argument supplied after the file name\n");
	else
	{
		printf("Enter a character to prepend to the string supplied on the command line\n");
		temp = getchar();
		printf("%s\n", ptrChar = prepend(temp, *(argv + 1)));
		free(ptrChar);
	}
 
	return(0);
}

Output:

lab46:~/Library$ ./appendL Joh
Enter a character to append to the string supplied on the command line
n
John
lab46:~/Library$ ./prependL ine
Enter a character to prepend to the string supplied on the command line
R
Rine
lab46:~/Library$

int occurrences(char *, char)
The function occurrences takes as function parameters a character and a character pointer (the base address of a character array, a string). occurences returns the number of times a particular character occurs in a string up to the maximum size of a integer.
Example code:

//John T. Rine
//September 23, 2011
 
#include<stdio.h>
#include "jr.h"
 
int main(int argc, char **argv)
{
	char c;
	int check;
	if (argc == 1) printf("Should be at least one command line argument supplied after the file name\n");
	else
	{
		printf("Enter a character to search the string\n");
		c = getchar();
		printf("Number of occurrences of %c within the string is %d\n", c, occurrences(*(argv + 1), c));
 
	}
	return 0;
 
}

Output:

lab46:~/Library$ ./occurrencesL "John Thomas Rine"
Enter a character to search the string
n
Number of occurrences of n within the string is 2
lab46:~/Library$

int find(char *, char)
The function find takes as function parameters a character and a character pointer (the base address of a character array, a string). find returns the first position in the string supplied as a parameter up to the maximum size of an integer.
Example code:

//John T. Rine
//September 23, 2011
 
#include<stdio.h>
#include "jr.h"
 
int main(int argc, char **argv)
{
	char c;
	int check;
	if (argc == 1) printf("Should be at least one command line argument supplied after the file name\n");
	else
	{
		printf("Enter a character to search the string\n");
		c = getchar();
		check = find(*(argv + 1), c);
		if (check != -1) printf("First position of the character within the string is %d\n", check);
		else printf("Character not found\n");
	}
	return 0;
 
}

Output:

lab46:~/Library$ ./findL
Should be at least one command line argument supplied after the file name
lab46:~/Library$ ./findL "Four score and seven years ago"
Enter a character to search the string
s
First position of the character within the string is 5
lab46:~/Library$

char *insert(char, char *, int)
The function insert takes as its function parameters a character and a character pointer (the base address of a character array, a string) and an integer representing the position in the string where the character is to be inserted. insert returns a pointer to a string which is composed of the original string with the character supplied as a parameter inserted at the position parameter.
Example code:

//John T. Rine
//September 23, 2011
 
#include<stdio.h>
#include<stdlib.h>
#include "jr.h"
 
int main(int argc, char **argv)
{
	char temp = 127, temp2;
	int number;
	char *ptrChar;
	int count;
 
	if (argc == 1) printf("Should be at least one command line argument supplied after the file name\n");
	else
	{
		printf("Enter a character to insert into the string supplied on the command line\n");
		temp = getchar();
		getchar();	//flush!!!
		printf("Enter a number representing the position in which to place the character\n");
		temp2 = getchar();
		getchar();	//flush!!!
		number = temp2 - 48;
		printf("%s\n", ptrChar = insert(temp, *(argv + 1), number));
		free(ptrChar);
	}
 
	return(0);
}

Output:

lab46:~/Library$ ./insertL "John homas"
Enter a character to insert into the string supplied on the command line
T
Enter a number representing the position in which to place the character
5
John Thomas
lab46:~/Library$

char *concat(char *, char *)
The function concat takes as its function parameters two character pointers (the base addresses of a character arrays-strings). concat returns a character pointer to a string composed of the second string concatenated to the first, that is it tacks the second string has been tacked onto the end of the first.
Example code:

//John T. Rine
//September 23, 2011
 
#include<stdio.h>
#include<stdlib.h>
#include "jr.h"
 
int main(int argc, char **argv)
{
	char *ptrString;
	printf("%s\n", ptrString = concat(*(argv + 1), *(argv + 2)));
	free(ptrString);
	return 0;
}

Output:

lab46:~/Library$ ./concatL "John Thomas" " Rine"
John Thomas Rine
lab46:~/Library$

char *toLower(char *)
The function toLower takes as its function parameter a character pointer (the base address of a character array, a string). It returns a character pointer to a string whose letters have been converted to lower case.
Example code:

#include<stdio.h>
#include<stdlib.h>
#include "jr.h"
 
int main(int argc, char **argv)
{
	char temp;
	char *ptrChar;
 
	if (argc != 2) printf("Should be one command line argument supplied after the file name\n");
	else
	{
		printf("%s\n", ptrChar = toLower(*(argv + 1)));
		free(ptrChar);
	}
		return 0;
}

Output:

lab46:~/Library$ ./toLowerL "JoHn thOmas rInE"
john thomas rine
lab46:~/Library$

char *toUpper(char *)
The function toUpper takes as its function parameter a character pointer (the base address of a character array, a string). It returns a character pointer to a string whose letters have been converted to upper case.
Example code:

#include<stdio.h>
#include<stdlib.h>
#include "jr.h"
 
int main(int argc, char **argv)
{
	char temp;
	char *ptrChar;
 
	if (argc != 2) printf("Should be one command line argument supplied after the file name\n");
	else
	{
		printf("%s\n", ptrChar = toUpper(*(argv + 1)));
		free(ptrChar);
	}
	return 0;
}

Output:

lab46:~/Library$ ./toUpperL "jOhN rInE"
JOHN RINE
lab46:~/Library$

//jr.h
//John T. Rine
//September 23, 2011
 
#ifndef _JRLIB_H
#define _JRLIB_H
 
int cntChars(char *);
char *append(char, char *);
char *prepend(char, char *);
int occurrences(char *, char);
int find(char *, char);
char *insert(char, char *, int);
char * concat(char *, char *);
char *toLower(char *);
char *toUpper(char *);
 
#endif 

//jr.c
//John T. Rine
//September 23, 2011
 
//lab46:~$ gcc -c jr.c -o jr.o
//lab46:~$ ar crs libjr.a jr.o
//lab46:~$ gcc -I. testStrings.c -o testStrings libjr.a
 
#include<stdlib.h>
#include<stdio.h>
 
int cntChars(char *inputString)
{
	// returned value "count" does not include '\0'
	int count = 0;
	while(*(inputString + count) != '\0') ++count;
	return(count);
}
 
char *append(char inputChar, char *inputString)
{
	//element      0    1    2
	//count = 0   '\0'
	//count = 1    A   '\0'
	//count = 2    M    y   '\0'
 
	int count, i;
	char * pChar;
	count = cntChars(inputString);
	if (!(pChar = (char *) malloc(sizeof(char) * (count + 2))))
	{
		fprintf(stderr,"Insufficient memory");
		exit(1);  
	}
	else
	{
		for(i = 0; i <= (count - 1); i++) *(pChar + i) = *(inputString + i);
		*(pChar + count) = inputChar;
		if(inputChar != '\0') *(pChar + count + 1) = '\0';
		return(pChar);
	}
}
 
char *prepend(char inputChar, char *inputString)
{
	//element      0    1    2
	//count = 0   '\0'
	//count = 1    A   '\0'
	//count = 2    M    y   '\0'
 
	int count, i;
	char * pChar;
	count = cntChars(inputString);
	if (!(pChar = (char *) malloc(sizeof(char) * (count + 2))))
	{
		fprintf(stderr,"Insufficient memory");
		exit(1);  
	}
	else
	{
		*pChar = inputChar;
		for(i = 1; i <= (count + 1); i++) *(pChar + i) = *(inputString + i - 1);
		return(pChar);
	}
}
 
int occurrences(char *inputString, char c)
{
	int i = 0;
	int r = 0;
	while (*(inputString + i) != '\0')
	{
		if(*(inputString + i) == c) r++;
		i++;
	}
	return r;
}
 
int find(char *inputString, char c)
{
	int i = 0;
	int r = -1;
	while (*(inputString + i) != '\0')
	{
		if(*(inputString + i) == c)
		{
			r = i;
			break;
		}
		i++;
	}
	return r;
}
 
char *insert(char inputChar, char *inputString, int position)
{
	//element      0    1    2
	//count = 0   '\0'
	//count = 1    A   '\0'
	//count = 2    M    y   '\0'
 
	int count, i;
	char * pChar;
 
	count = cntChars(inputString);
	if (!(pChar = (char *) malloc(sizeof(char) * (count + 2))))
	{
		fprintf(stderr,"Insufficient memory");
		exit(1);  
	}
	else
	{
		i = 0;
		while(i <= (count + 1))
		{
			if(i < position) *(pChar + i) = *(inputString + i);
			else if	(i == position) *(pChar + i) = inputChar;
			else *(pChar + i) = *(inputString + i - 1);
			i++;
		}
		return(pChar);
	}
}
 
char * concat(char *s1, char *s2)
{
	char *r = NULL;
	int count = 0;
	int countTotal = 0;
	int i;
	int j = 0;
 
	count = cntChars(s1);
	countTotal = count + cntChars(s2);
	if(!(r = (char *) malloc(sizeof(char) * (countTotal + 1))))
	{
		fprintf(stderr,"Insufficient memory");
		exit(1);
	}
	else
	{
		for(i = 0 ; i < count; i++) *(r + i) = *(s1 + i);
		while(i < countTotal)
		{
			*(r + i) = *(s2 + j);
			j++;
			i++;
		}
		*(r + countTotal) = '\0';
		return r;
	}
}
 
char *toLower(char *inputString)
{
	int count, i;
	char * pChar;
	count = cntChars(inputString);
	if (!(pChar = (char *) malloc(sizeof(char) * (count + 1))))
	{
		fprintf(stderr,"Insufficient memory");
		exit(1);  
	}
	else
	{
		for(i = 0; i <= count; i++)
		{
			if(*(inputString + i) >= 'A' && *(inputString + i) <= 'Z') *(pChar + i) = *(inputString + i) + 32;
			else *(pChar + i) = *(inputString + i);
		}
		return(pChar);
	}
}
 
char *toUpper(char *inputString)
{
	int count, i;
	char * pChar;
	count = cntChars(inputString);
	if (!(pChar = (char *) malloc(sizeof(char) * (count + 1))))
	{
		fprintf(stderr,"Insufficient memory");
		exit(1);  
	}
	else
	{
		for(i = 0; i <= count; i++)
		{
			if(*(inputString + i) >= 'a' && *(inputString + i) <= 'z') *(pChar + i) = *(inputString + i) - 32;
			else *(pChar + i) = *(inputString + i);
		}
		return(pChar);
	}
}