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#1 qqaa007   User is offline

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[Question] Replace substring

Posted 20 March 2013 - 06:13 AM


I have this code here:

#include <stdio.h>

int isSubstring (char s[], char t[])
int i, j, k, pos;
pos = -1;
for (i = 0; s[i] != '\0'; i++)
for (j = i, k = 0; t[k] != '\0' && s[j] == t[k]; j++, k++)
if (k > 0 && t[k] == '\0')
pos = i;
return pos;

int main()
char s[] = "All work and no play makes Jack a dull boy.";
char t[5];
char name;

printf("Name to substitute: ");

/*Here - This bit not sure what to put*/
name = isSubstring (s, "Jack" , t);

printf("%s %s",name );
/*To here*/


I wnat to substitutes the text Jack in the string variable quote with the content of the variable name.

like this;

Name to substitute: Mark
	All work and no play makes Mark a dull boy

I don't what to put there so can i get help
thank you

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Replies To: [Question] Replace substring

#2 jimblumberg   User is online

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Re: [Question] Replace substring

Posted 20 March 2013 - 06:52 AM

First find an indentation style you like and use it consistently. The way your code is now formatted makes it hard to read.

As to the actual problem, you may want to investigate the strstr() function.

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#3 Adak   User is offline

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Re: [Question] Replace substring

Posted 20 March 2013 - 10:42 AM

Try to avoid working with individual chars in this job. You want to:

1) use strstr() to find the first letter of "Jack". Everything past the J in Jack, is the "tail". Move it to another array. The first part of the substring "All work and no play makes ", is the "head" part.

2) strcat() "Mark" onto the end of the "head" part substring: "All work and no play makes Mark"

3) now count over "Jack", from the tail, by using it's strlen(). You can use an index or a pointer to count up the needed four chars.

4) now strcat() this part ONLY of the tail, back onto the rest of the head portion.

Since Mark and Jack both have four letters in them, you can do this in a simpler way, but I'm not describing it because it fails anytime you have to work with Michael and Jack, or Laurel and Jack - anything that has an unequal number of chars in it.

Need I mention that string.h is required for this - no - I think not.
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