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Split string in C every white space

Asked 2010-12-22T20:15:32.637
70

I want to write a program in C that displays each word of a whole sentence (taken as input) at a seperate line. This is what I have done so far:


void manipulate(char *buffer);
int get_words(char *buffer);

int main(){
    char buff[100];

    printf("sizeof %d\nstrlen %d\n", sizeof(buff), strlen(buff));   // Debugging reasons

    bzero(buff, sizeof(buff));

    printf("Give me the text:\n");
    fgets(buff, sizeof(buff), stdin);

    manipulate(buff);
    return 0;
}

int get_words(char *buffer){                                        // Function that gets the word count, by counting the spaces.
    int count;
    int wordcount = 0;
    char ch;

    for (count = 0; count < strlen(buffer); count ++){
        ch = buffer[count];
        if((isblank(ch)) || (buffer[count] == '\0')){                   // if the character is blank, or null byte add 1 to the wordcounter
            wordcount += 1;
        }
    }
    printf("%d\n\n", wordcount);
    return wordcount;
}

void manipulate(char *buffer){
    int words = get_words(buffer);
    char *newbuff[words];
    char *ptr;
    int count = 0;
    int count2 = 0;
    char ch = '\n';
    
    ptr = buffer;
    bzero(newbuff, sizeof(newbuff));

    for (count = 0; count < 100; count ++){
        ch = buffer[count];
        if (isblank(ch) || buffer[count] == '\0'){
            buffer[count] = '\0';
            if((newbuff[count2] = (char *)malloc(strlen(buffer))) == NULL) {
                printf("MALLOC ERROR!\n");
                exit(-1);
            }
            strcpy(newbuff[count2], ptr);
            printf("\n%s\n",newbuff[count2]);
            ptr = &buffer[count + 1];
            count2 ++;
        }
    }
}

Although the output is what I want, I have really many black spaces after the final word displayed, and the malloc() returns NULL so the MALLOC ERROR! is displayed in the end. I can understand that t

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1 Answer

5

For the fun of it here's an implementation based on the callback approach:

const char* find(const char* s, const char* e, int (*pred)(char)) {
    while( s != e && !pred(*s) ) ++s;
    return s;
}

void split_on_ws(const char* s,
                 const char* e,
                 void (*callback)(const char*, const char*)) {
    const char* p = s;
    while( s != e ) {
        s = find(s, e, isspace);
        callback(p, s);
        p = s = find(s, e, isnotspace);
    }
}

void handle_word(const char* s, const char* e) {
    // handle the word that starts at s and ends at e
}

int main() {
    split_on_ws(some_str, some_str + strlen(some_str), handle_word);
}
answered 2010-12-22T20:38:59.930

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