strcpy.c

/*
 * STRCPY -- show 4 different ways of copying a string
 *
 * Usage: strcpy
 *
 * Inputs:tring to be copied
 * Output: 4 copies, each done differently
 * Exit Code: EXIT_SUCCESS
 *
 * Matt Bishop, ECS 36A
 * April 12, 2024	original version
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*
 * macros
 */
#define MAXLINE			1000	/* maximum allowed line length */

/*
 * prototypes -- all are different functions that do the same
 * thing: copy a string from old to new
 */
void str1copy(char new[], char old[]);
void str2copy(char new[], char old[]);
void str3copy(char new[], char old[]);
void str4copy(char *new, char *old);

/*
 * echo a line from the input to the output
 */
int main(void)
{
	char buf[MAXLINE];				/* input buffer */
	char new[MAXLINE];				/* output buffer */
	/*
	 * read a line, then write it out
	 */
	while(printf("type away!> "), fgets(buf, MAXLINE, stdin) != NULL){
		/* #1 to: copy it to the new buffer and print it */
		str1copy(new, buf);
		printf("1> ");
		fputs(new, stdout);
		/* #2: copy it to the new buffer and print it */
		str2copy(new, buf);
		printf("2> ");
		fputs(new, stdout);
		/* #3: copy it to the new buffer and print it */
		str3copy(new, buf);
		printf("3> ");
		fputs(new, stdout);
		/* #4: copy it to the new buffer and print it */
		str4copy(new, buf);
		printf("4> ");
		fputs(new, stdout);
	}

	/*
	 * say goodbye!
	 */
	return(0);
}

/*
 * make a copy of a string
 *
 * arguments:		char old[]		original string
 *			char new[]		buffer for copy
 *
 * returns:		nothing, but on return new contains a copy of old
 *
 * exceptions:		none, but length of old and new are not checked
 */
void str1copy(char new[], char old[])
{
	int i;		/* counter in a for loop */
	/*
	 * do it char by char
	 */
	for(i = 0; old[i] != '\0'; i++)
		new[i] = old[i];
	/* tack on the terminator */
	new[i] = '\0';
}

/*
 * make a copy of a string
 *
 * arguments:		char old[]		original string
 *			char new[]		buffer for copy
 *
 * returns:		nothing, but on return new contains a copy of old
 *
 * exceptions:		none, but length of old and new are not checked
 */
void str2copy(char new[], char old[])
{
	int i;		/* counter in a for loop */
	/*
	 * do it char by char
	 */
	for(i = 0; old[i]; i++)
		new[i] = old[i];
	/* tack on the terminator */
	new[i] = '\0';
}

 /*
 * make a copy of a string
 *
 * arguments:		char old[]		original string
 *			char new[]		buffer for copy
 *
 * returns:		nothing, but on return new contains a copy of old
 *
 * exceptions:		none, but length of old and new are not checked
 */
void str3copy(char new[], char old[])
{
	int i;		/* counter in a for loop */
	/*
	 * do it char by char
	 */
	for(i = 0; new[i] = old[i]; i++)
		;
}

/*
 * make a copy of a string
 *
 * arguments:		char old[]		original string
 *			char new[]		buffer for copy
 *
 * returns:		nothing, but on return new contains a copy of old
 *
 * exceptions:		none, but length of old and new are not checked
 */
void str4copy(char *new, char *old)
{
	/*
	 * do it char by char
	 */
	while(*new++ = *old++)
		;
}

Matt Bishop Office: 2209 Watershed Sciences Phone: +1 (530) 752-8060 Email: mabishop@ucdavis.edu

ECS 36A, Programming & Problem Solving Version of April 2, 2024 at 12:13PM

You can get the raw source code here.