remove_the_parentheses.c

/*

    remove_the_parentheses.c

https://www.codewars.com/kata/5f7c38eb54307c002a2b8cc8
https://www.codewars.com/kata/5f7c38eb54307c002a2b8cc8/train/c
https://www.codewars.com/kata/5f7c38eb54307c002a2b8cc8/solutions/c

I recommend the site www.codewars.com because it is great for learning programming languages.
Its advantage over other similar sites is that once you solve the problem,
you can see how other people have solved the same problem.
And much can be learned from others ...

Remove the parentheses

In this kata you are given a string for example:

"example(unwanted thing)example"
Your task is to remove everything inside the parentheses as well as the parentheses themselves.

The example above would return:

"exampleexample"
Notes
Other than parentheses only letters and spaces can occur in the string.
Don't worry about other brackets like "[]" and "{}" as these will never appear.
There can be multiple parentheses.
The parentheses can be nested.


    You can find all my C programs at Dragan Milicev's pastebin:

    https://pastebin.com/u/dmilicev

*/

#include <stdio.h>
#include <string.h>

// implementation of C function strcpy()
void my_strcpy(const char *str_in, char *str_out) {
    //while(*str_in != '\0'){
    while(*str_in){
        *str_out = *str_in;
        str_in++;
        str_out++;
    }

    *str_out = '\0';    // include the terminating null character
}

// implementation of C function strcpy()
void my_strcpy1(const char *str_in, char *str_out) {
    while(*str_in)
        *str_out++ = *str_in++;
    *str_out = '\0';    // include the terminating null character
}

void count_parentheses(const char *str_in, char *str_out) {
    int i=0, j=0, opened_parentheses=0, closed_parentheses=0, active_parentheses=0;
    while( *(str_in+i) ){
        if( *(str_in+i) == '(' ){
            opened_parentheses++;
            active_parentheses++;
        }
        if( *(str_in+i) == ')' ){
            closed_parentheses++;
            active_parentheses--;
        }
        printf("\n i = %3d  *(str_in+i) = %c  opened = %d   closed = %d  active = %d \n",
                i, *(str_in+i), opened_parentheses, closed_parentheses, active_parentheses );
        if( active_parentheses == 0 && *(str_in+i) != ')' ){
            *(str_out+j) = *(str_in+i); // copy
            j++;
        }
        i++;
    }
    *(str_out+j) = '\0';                // include the terminating null character
}

// do not allocate memory for return value
// assign to the provided pointer *str_out
void remove_parentheses(const char *str_in, char *str_out) {
    int i=0, j=0, active_parentheses=0;
    while( *(str_in+i) ){
        if( *(str_in+i) == '(' )
            active_parentheses++;
        if( *(str_in+i) == ')' )
            active_parentheses--;
        if( active_parentheses == 0 && *(str_in+i) != ')' ){
            *(str_out+j) = *(str_in+i); // copy
            j++;
        }
        i++;
    }
    *(str_out+j) = '\0';                // include the terminating null character
}

void remove_parentheses1(const char *str_in, char *str_out) {
    int active_parentheses=0;
    while( *str_in ){
        if( *str_in == '(' )
            active_parentheses++;
        if( *str_in == ')' )
            active_parentheses--;
        if( active_parentheses == 0 && *str_in != ')' ){
            *str_out = *str_in;     // copy
            str_out++;
        }
        str_in++;
    }
    *str_out = '\0';                // include the terminating null character
}

void remove_parentheses2(const char *str_in, char *str_out) {
  int i, k, c = ' ', count = 0;
  for(i=0, k=0; c!='\0'; i++){
    c = str_in[i];
    if( c == '(' ) count++;
    if( !count ) str_out[k++] = c;
    if(c == ')') count--;;
  }
}

void remove_parentheses3(const char *in, char *out){
    int n;
    for (n=0; *in; in++){
        n += *in == '(';
        if (!n)
            *out++ = *in;
        n -= *in == ')';
    }
    *out = 0;   // must be 0, not '\0' !
}

int main(void){
    int i, n;
    char str_in[1024], str_out[1024];

    sprintf(str_in, "example(unwanted thing)example");
//  sprintf(str_in, "example(unwanted thingexample)");
//  sprintf(str_in, "exam(ple(unwanted th)ing)example");
//  sprintf(str_in, "ex(amp)le(unwanted thing)example");
//  sprintf(str_in, "ex(a(mp)le(unwanted thing)ex)ample");
//  sprintf(str_in, "fgLiXvSh YTkLFJtSKCiLSEVlQybsQcxWNtQfiX((NbocKHIrhQPMf(XITL G)(AxoaCj)Gavv(lcJTh)tW)yoWUe()LoM)L");
//  sprintf(str_in, "cRoxCdzqCPVTsOqEeLIspROzLzVFzHHBwJLYzh  JHF(fVDjqZCtAaFizxNLb(jkBHW PIMvmoueWLo(HDp)qU DbAlTsiaTP(DB(mKnnbsWzt)TWV)(N)zBKL) T)");

//  printf("\n str_in  = |%s| \n", str_in);

//  count_parentheses(str_in, str_out);
//  remove_parentheses(str_in, str_out);
    remove_parentheses1(str_in, str_out);
//  remove_parentheses2(str_in, str_out);
//  remove_parentheses3(str_in, str_out);

//  my_strcpy(str_in,str_out);
//  my_strcpy1(str_in,str_out);

    printf("\n str_in  = |%s| \n", str_in);
    printf("\n str_out = |%s| \n", str_out);

    printf("\n\n");
    return 0;
} // main()