строки 10

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

int check(const char *s) {
    const int n = strlen(s);

    int counter = 0;
    for (int i = 0; i < n; ++i) {
        if (s[i] == '(') {
            counter ++;
        }
        if (s[i] == ')') {
            counter --;
        }

        if (counter < 0)
            return 0;
    }

    if (counter != 0)
        return 0;
    return 1;
}

void print_str(char* s) {
    const int n = strlen(s);

    if (check(s) == 0) {
        printf("check failed\n");
        return;
    }

    int counter = 0;
    for (int i = 0; i < n; ++i) {
        if (s[i] == '(') {
            counter ++;
            printf("%c", s[i]);
            continue;
        }
        if (s[i] == ')') {
            counter --;
            printf("%c", s[i]);
            continue;
        }

        if (counter == 0)
            printf("%c", s[i]);
    }
}

int main() {
    char str[4001];

    printf("enter string: ");
    scanf("%4001[^\n]", str);

    print_str(str);

    return 0;
}