Reading input in C

fast_reading_input.c

/* https://bugdivine.blogspot.com/p/fast-input-reader-in-cc.html */
#include <stdio.h>

int fastRead_int() {
    register int c = getchar_unlocked();
    int x;
    x = 0;
    int neg = 0;
    for(; ((c<48 || c>57) && c != '-'); c = getchar_unlocked());
    if(c=='-') {
        neg = 1;
        c = getchar_unlocked();
    }
    for(; c>47 && c<58 ; c = getchar_unlocked()) {
        x = (x<<1) + (x<<3) + c - 48;
    }
    if(neg) x = -x;
    return x;
}

void fastRead_string(char *str, char delim) {
    register char c = 0;
    register int i = 0;
    while (c < 33)
        c = getchar_unlocked();
    /*c != ' ' || c != '\t' || c != '\n'*/
    while (c != delim) {
        str[i] = c;
        c = getchar_unlocked();
        i = i + 1;
    }
    str[i] = '\0';
}

int main() {
    int n;
    char s[100];
    n = fastRead_int();
    printf("%d\n", n);
    fastRead_string(s, '\n');
    printf("%s\n", s);
    return 0;
}