#include <stdio.h>

#define isnum(x) ('0' <= (x) && (x) <= '9')
#define tonum(x) ((x) - '0')

char str[] = "M 123 12 45 478 235 124 12 9";

int x[8];

// Returns:
// Number of variables matched
// 0 - no variables were matched
int myscanf(char *str, char *format) {
    int n = 0; // number of matches
    int *xp;
    xp = x;
    for(; format != '\0'; format++) {
        switch(*format) {
        case '%':
            format++;
            switch(*format) {
            case 'd':
                *xp = 0;
                if(!isnum(*str)) return n;
                for(; isnum(*str); str++) {
                    *xp *= 10;
                    *xp += tonum(*str);
                }
                xp++;
                n++;
            }
            break;
        default:
            // want *str == *format
            if(*str == '\0' || *str == '\n' || *str == '\r') return n;
            if(*str != *format) return n;
            str++;
            break;
        }
    }
    return n;
}

// Returns number of variables matched
int mysearch(char *str, char *format) {
    int n;
    for(; *str != '\0'; str++) {
        n = myscanf(str, format);
        if(n) return n;
    }
    return 0;
}

int main() {
    int i;
    printf("%d\n", myscanf(str, "M %d %d %d %d %d %d %d %d %d"));
    printf("%d\n", mysearch(str, "M %d %d %d %d %d %d %d %d %d"));
    printf("%d %d %d %d\n", x[0], x[1], x[2], x[3]);
    return 0;
}