How to extract a substring from a string in C?

Question

I tried using strncmp but it only works if I give it a specific number of bytes I want to extract.

char line[256] = This \"is\" an example. //I want to extr         


        

Answer 1

Here is a long way to do this: Assuming string to be extracted will be in quotation marks (Fixed for error check suggested by kieth in comments below)

#include 
#include 
#include 

int main(){

    char input[100];
    char extract[100];
    int i=0,j=0,k=0,endFlag=0;

    printf("Input string: ");
    fgets(input,sizeof(input),stdin);
    input[strlen(input)-1] = '\0';

    for(i=0;i

Output(1):

$ ./test
Input string: extract "this" from this string
Extract = this

Output(2):

$ ./test
Input string: Another example to extract "this gibberish" from this string
Extract = this gibberish

Output(3):(Error check suggested by Kieth)

$ ./test

Input string: are you "happy now Kieth ?
1.Your code only had one quotation mark.
2.So the code extracted everything after that quotation mark
3.To make sure buffer overflow doesn't happen in this case:
4.Modify the extract buffer size to be the same as input buffer size

extracted string: happy now Kieth ?

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Although not asked for it -- The following code extracts multiple words from input string as long as they are in quotation marks:

#include 
#include 
#include 

int main(){

    char input[100];
    char extract[50];
    int i=0,j=0,k=0,endFlag=0;

    printf("Input string: ");
    fgets(input,sizeof(input),stdin);
    input[strlen(input)-1] = '\0';

    for(i=0;i

Output:

$ ./test
Input string: extract "multiple" words "from" this "string"
Extract = multiplefromstring