String help in C

None · 2014-04-17T17:35:05

Hello, I am trying to write a program that counts how many times a letter occurs in a string. I know there's easy ways to do it, but I want to use the strchr function to have a search key. I wrote this and for some reason, nothing even happens when I run it! No errors or nothing so I'm not sure what the problem could be! Any help is appreciated #include <stdio.h> #include <string.h> int main(int argc, const char * argv[]) { const char * random_text = "Once there was this really old man who tranformed into dust. The end!"; int counter = 0; int searchKey = 'd'; char * strPtr = strchr(random_text, searchKey); do { if(strPtr != NULL) counter++; strPtr = strchr(random_text+1, searchKey); } while (strPtr != NULL); printf("%s\n%s\n\n%s%c%s%d%s", "The text:", random_text, "The occurence of ", searchKey, " happened ", counter, " times.\n"); return 0; }

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Started by NUCLEAR RABBIT April 17, 2014 03:25 AM

11 comments, last by alvaro 10 years ago

alvaro

21,604

April 17, 2014 05:18 PM

    for (size_t counter = 0; counter < strlen(randomString); ++counter);

Oh, now this might take time that grows quadratically with the length of the string, depending on how smart the compiler is.

NightCreature83

5,061

April 17, 2014 05:27 PM

    for (size_t counter = 0; counter < strlen(randomString); ++counter);
Oh, now this might take time that grows quadratically with the length of the string, depending on how smart the compiler is.

in release that should compile out, compilers are pretty good at seeing what is changing in a loop and what is not.

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alvaro

21,604

April 17, 2014 05:35 PM

    for (size_t counter = 0; counter < strlen(randomString); ++counter);
Oh, now this might take time that grows quadratically with the length of the string, depending on how smart the compiler is.
in release that should compile out, compilers are pretty good at seeing what is changing in a loop and what is not.

It's still good practice to write code so you don't have to trust the compiler to do something smart like that. In this case you just need to write

for (size_t counter = 0; randomString[counter] != '\0'; ++counter);

String help in C

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String help in C

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