Permission Flags

Lab C Intermediate 20 points

Use #define READ 4, WRITE 2, EXEC 1. Read a permission number 0–7 and a list of operations (+r, -w, …) that add or remove flags. Print the final number and the rwx string (with - for missing).

Input

Line 1: starting value. Line 2: k. Then k operations.

Output

One line: N rwx

Example

Input

4
2
+w
+x

Output

7 rwx

Sample input available Sample output available

Editor

Hints

Set a flag with |, clear it with & ~flag, test it with &.

Solution explanation

This is exactly how Unix file permissions (like 755) work.

Show solution

#include <stdio.h>
#define READ 4
#define WRITE 2
#define EXEC 1

int main() {
    int perm, k;
    char op[3];
    scanf("%d %d", &perm, &k);
    for (int i = 0; i < k; i++) {
        scanf("%s", op);
        int flag = EXEC;
        if (op[1] == 'r') flag = READ;
        else if (op[1] == 'w') flag = WRITE;
        if (op[0] == '+') perm = perm | flag;
        else perm = perm & ~flag;
    }
    printf("%d %c%c%c\n", perm, perm & READ ? 'r' : '-', perm & WRITE ? 'w' : '-', perm & EXEC ? 'x' : '-');
    return 0;
}

Output

Answer