Help w/ comparings two strings case sensitive

This is a discussion on Help w/ comparings two strings case sensitive within the C Programming forums, part of the General Programming Boards category; This is what i have for comparing two strings case sensitive. And i added a printf statement to test the ...

  1. #1
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    Help w/ comparings two strings case sensitive

    This is what i have for comparing two strings case sensitive. And i added a printf statement to test the numerical values of teh strings and the values are supposed to be the same but they are not. The plan was to use the numerical values to test, but i get different outputs.
    Code:
    #include <stdio.h>
    #include <conio.h>
    main()
    {
    	int loop=0, strone, strtwo; 
    	char str[80]={"cprog"};
    	char str2[80]={"cprog"};
    	
    
    strone=str;
    strtwo=str2;
    
    
    printf("%d", strone);
    printf("\n%d", strtwo);
    			
    /*this tests whether the two are same or not*/
    	/*	if(strone==strtwo)
    		{
    			printf("The strings are equal");
    		}		
    		else
    		printf("The strings are not equal");
    	
    	*/	getch();
    	
    
    }
    
    /*OUTPUT
    
    1244964
    1244884
    
      */
    -ikkin
    Last edited by ikkin; 11-12-2003 at 05:21 PM.

  2. #2
    The Defective GRAPE Lurker's Avatar
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    strcmpi(str1, str2) returns 1 if 2 strings are the same, excluding case, otherwise it returns 0 if they are different.

    EDIT: Don't forget to include string.h!!
    Last edited by Lurker; 11-12-2003 at 05:23 PM.
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  3. #3
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    ya i figured out how to compare two srings ignoring the case difference but i need it to be case sensitive__ any ideas?


    -ikkin

  4. #4
    The Defective GRAPE Lurker's Avatar
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    strcmp(str1, str2) is case sensitive - sorry, misread post .
    strcmpi(str1, str2) works the same way, but isnt case sensitive .
    Do not make direct eye contact with me.

  5. #5
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    Smile

    Thats okay

    But the problem is that i have to write my own function that compares the two strings

    Thanx.
    Last edited by ikkin; 11-12-2003 at 05:36 PM.

  6. #6
    Registered User linuxdude's Avatar
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    Code:
    #include <stdio.h>
    #include <stdlib.h>
    void my_strcmp(char *string1,char *string2); /*compares string one to string 2*/
    int main(){
            char strone[BUFSIZ];
            char strtwo[BUFSIZ];
            printf("Enter a string!\n");
            fgets(strone,sizeof(strone),stdin);
            printf("Enter another string!\n");
            fgets(strtwo,sizeof(strtwo),stdin);
            printf("%s%s",strone,strtwo);
            my_strcmp(strone,strtwo);
            return 0;
    }
    void my_strcmp(char *string1,char *string2){
            int str1=0,str2=0,diff,;
            while(string1[str1]!='\0'){
                    str1++;
            }
            while(string2[str2]!='\0'){
                    str2++;
            }
            diff=str1-str2;
            printf("diff = %i\n",diff);
            printf("str1 = %i\nstr2 = %i\n",str1,str2);
    }
    This is a start I don't feel like doing the whole case sensitive side of this program if anyone wants to build off of this I wouldn't mind
    Last edited by linuxdude; 11-12-2003 at 09:19 PM.

  7. #7
    Guest Sebastiani's Avatar
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    Since this is homework, you should figure this out on your own, right?

    The basic idea is that uppercase letters and and their lowercase equivalent are always a certain distance apart on an ASCII chart.

    Here's the code for a simple comparison function you can easily modify into strcmp() (and eventually, strcasecmp()):

    Code:
    int
     streq(const char s1[], const char s2[])
    {
     int index;
    
        for(index = 0; (s1[index] != 0) && (s2[index] != 0); ++index)
       {
            if(s1[index] != s2[index])  return 0;
       } 
      
     // make sure we've reached the end of both strings:
    
        if((s1[index] != 0) || (s2[index] != 0))  return 0; 
    
     return 1;
    }
    Code:
    bool fun(bool value)
    {
        return std::pow(std::exp(1), std::complex<float>(0, 1) 
        * std::complex<float>(std::atan(1)*(1 << (value + 2))))
        .real() > 0;
    }

  8. #8
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    Since this uses pointers, I doubt the teacher will accept it - but this is how string comparisons work
    Code:
    int my_strcmp(const char *a, const char *b){
           int i=0;
           while (*(a+i)==*(b+i) && *(a+i) && *(b+i)) i++;
           return *(a+i)-*(b+i);
    
    }
    Note that you return the difference at the end.
    This my_strcmp returns 0 if equal, -1 if a < b and 1 if a > b

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