Language: C

#include <stdio.h>

int main(){
        char a[100];
        char b[100];
        char c[100];
        char turn = 'a';
        char result = 0;
        char ca = 0;
        char cb = 0;
        char cc = 0;

        scanf("%s", a);
        scanf("%s", b);
        scanf("%s", c);

        while(result == 0){
                switch(turn){
                        case 'a':
                                ca++;
                                if(a[ca] == 0){
                                        result = 'A';
                                        break;
                                }
　　　　　　　　　　turn = a[ca];
                                break;
                        case 'b':
                                cb++;
                                if(c[cc] == 0){
                                        result = 'C';
                                        break;
                                }
                                turn = b[cb];
                                break;
                        case 'c':
                                cc++;
                                if(c[cc] == 0){
                                        result = 'C';
                                        break;
                                }
                                turn = c[cc];
                                break;
                }
        }
        printf("%c\n", result);
        return 0;

}


Compiler output:
main.c: In function 'main':
main.c:25:1: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      | ^~~~~~~~
main.c:25:3: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      |         ^~~~~~~~
main.c:25:5: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      |                 ^~~~~~~~
main.c:25:7: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      |                         ^~~~~~~~
main.c:25:9: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      |                                 ^~~~~~~~
main.c:25:11: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      |                                         ^~~~~~~~
main.c:25:13: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      |                                                 ^~~~~~~~
main.c:25:15: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      |                                                         ^~~~~~~~
main.c:25:17: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      |                                                                 ^~~~~~~~
main.c:25:19: error: stray '\343' in program
   25 | <U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000><U+3000>turn = a[ca];
      |                                                                         ^~~~~~~~