find and replace command?

I know it should be simple, but I am sooo bad at this... could someone give a simple example of a find and replace command that takes arguments? I kno it should be something along the lines of (P.S. this came from another thread, and was Quzah's code:
#include <stdio.h>
int main (char *filename)
{
FILE *fp = NULL;
int c = 0;

if( (fp = fopen(filename, "r" )) != NULL)
{
while( (c = fgetc( fp )) != EOF )
{
if( c == '<' )
{
do printf( "%c", c ); while( (c = fgetc( fp )) != EOF && c != '>' );
printf(">\n");
}
}
fclose( fp );
}
else
printf("Error opening file.\n");
return 0;
}

/**** IT IS QUZAH'S CODE! NOT MINE! (of course, I could never program something so simple and fast....)****/

Did you bother to look at this in your other thread:

Code:

#include <stdio.h> 

int main (int argc, char * argv[]) 
{ 
	FILE * fp = NULL;
	int c = 0; 

	if (argc == 2)
	{
		if( (fp = fopen(argv[1], "r" )) != NULL) 
		{ 
			while( (c = fgetc( fp )) != EOF ) 
			{ 
				if( c == '<' ) 
				{ 
					do printf( "%c", c );
					while( (c = fgetc( fp )) != EOF && c != '>' ); 
					printf(">\n"); 
				} 
			} 
			fclose( fp ); 
		} 
		else 
		printf("Error opening file.\n"); 
	}
	/* remove this if you do not with to see the path to your program */
	printf(argv[0]);
	return 0; 
}

Refer to this for more:

Code:

/*

	Program:
	CmdLine.c
	
	Purpose:
	Demonstrates the use of command line parameters.

	argc = command line argument count
	
	argv[number] = individual commands read
	0 = the path to the current program, always a given
	1 = parameter
	2 = parateter
	etc
	
*/

#include <stdio.h>

void default_message(void);

int main( int argc, char * argv[] )  
{
	if (argc == 2)
	/* if there was a parameter besides the path to this program */
	{
		if(argv[1][0] == '?')
		/* if the parameter was a question mark */
		{
			printf("Help stuff would go here.\n");
		}
		else
		/* if the parameter was not a question mark, print whatever it was */
		{
			printf("%s \n", argv[1]);
		}
	}
	else if ( argc >= 3 )
	/* if there were more than 2 parameters besides the path to the program */
	{
		printf("Invalid input:\n");
		printf("Only one command-line parameter allowed.\n");
	}
	else
	/* if there were no paramters at all */
	{
		default_message();
	}
	return 0;
}

void default_message(void)
{
	printf("CmdLine.exe:\n");
	printf("The purpose of this program is to demonstrate command line arguments.\n");
	printf("This program will print whatever you type on the screen.\n\n");
	printf("Example:\n");
	printf("C:\\>CmdLine.exe Hmmm\n");
	printf("Hmmm\n");
}

Use code tags.

Thx....