compares 2 arguments and replaces characters

This is a discussion on compares 2 arguments and replaces characters within the C Programming forums, part of the General Programming Boards category; it doesn't work -help?????????????? Code: #include <stdio.h> #include <string.h> #include <ctype.h> #include <stdlib.h> main (int argc, char *argv[]) { nt ...

  1. #1
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    compares 2 arguments and replaces characters

    it doesn't work -help??????????????

    Code:
    #include <stdio.h>
    #include <string.h>
    #include <ctype.h>  
    #include <stdlib.h>
    
    
    main (int argc, char *argv[]) 
    {
    
    nt k, j ,i, len , siz, rep = 0; 
    
    char *s1; 
    char *s2;
    char s3[30];
    
    
    s1 = malloc (strlen(argv[1]) +1);
    strcpy (s1,argv[1]);
    
    s1 = malloc (strlen(argv[2]) +1);
    strcpy (s2,argv[2]); 
      
    len = strlen(s1); 
    siz = strlen(s2);
    
    while (rep <= 5)
    
    {
       while (NULL != fgets(s3, 30, stdin))   
    
        {
    
    if (strcmp(s1[0], '-')) && (strcmp(s1[1], 'f'))
    	
    	{
    	  
    	if (argc != 4)
    	 {
    		printf("invlaid number of arguments");
    		exit(1); 
    	 } 	
    		
    		for (k=0; k<= len; k++)
    
    			{
    	
    						
    			for (i=1; i<=len; i++)
     				
    				{
    		   		if ( 0==strcmp(s1[k], s1[i]) )
    					{
    									
    						strcpy(s1[k], s2[j]);
    					} 
    				j++; 
    				
    				}
    
    			fputs(s1,stdout);		
    				 
    		        }						            	    
     	}
       	
    }
    
    
    if ( 0==strcmp (s1[0], '-')) && ( 0==strcmp (s1[1],'f')) 
    {
    
    if (argc != 3)
    
    	{
    		printf("invalid number of arguments");
    		exit(1); 
    	} 	
    	
    
    		for (k=0; k<= len; k++)
    
    			{
    			   strcpy(s1[k], s2[j]);		
    			
                               j++; 
                            }
     
    		fputs( s1, stdout);
    }
    
    }
    	
    return 0;
    
    }

  2. #2
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    Code:
    s1 = malloc (strlen(argv[2]) +1);
    strcpy (s2,argv[2]);
    You got a small typo for s1/s2, meant to be:
    Code:
    s2 = malloc (strlen(argv[2]) +1);
    strcpy (s2,argv[2]);
    Also more: make sure you specify the return type for main, explictly use int main(int argc, char* argv[])

    Also did you bother to compile it? You got more syntax errors:

    Code:
    if ( 0==strcmp (s1[0], '-')) && ( 0==strcmp (s1[1],'f'))
    You are missing an extra set of brackets:
    Code:
    if (( 0==strcmp (s1[0], '-')) && ( 0==strcmp (s1[1],'f')))
    Last edited by 0rion; 04-13-2005 at 11:01 PM.

  3. #3
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    thanks for that

    it won't compile thats part of the problem

  4. #4
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    Well the compiler should generate errors when it encounters syntax errors and usually it tells you which lines its on so its usually easy to fix without further help. You should get used to reading the errors since you'll be stumped on what each error means if you got no one around ya

  5. #5
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    we are compiling in SSH
    none of the comments make sense
    it doesn't like my assignments strcpy etc it treats them as an error

    any other tips

  6. #6
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    If you want to compare individual characters you don't need to use strcmp().
    Likewise for strcpy(), what you are doing is this:
    Code:
       strcpy(s1[k], s2[j]);
    This would not work unless s1 is an array of strings. If you wanted to copy over the character in s2[j] into s1[k] then you just simply need to use the assignment operator:
    Code:
    s1[k] = s2[j];

  7. #7
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    s1 is a pointer to an array of strings

  8. #8
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    orion is right

    s1 is a pointer which acts like an array

    s1[1] it is equal to s1 +1

    u are incrmenting the s1 pointer by offset 1 to point to next element of the string

    s.s.harish

  9. #9
    Senior Member joshdick's Avatar
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    Quote Originally Posted by ssharish
    s1[1] it is equal to s1 +1
    Not quite.

    s1[1] evaluates to *(s1+1)

    (s1+1) is equivalent to &s1[1]

  10. #10
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    yes u are right joshdick

    i am an idiot

    thax for correcting me

    s.s.harish

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