Error(s):

source_file.c:4:6: warning: return type of ‘main’ is not ‘int’ [-Wmain]
 void main()
      ^
source_file.c: In function ‘main’:
source_file.c:7:18: error: invalid operands to binary & (have ‘int *’ and ‘int’)
 scanf("%d%d%d",&p&r&t);
                  ^
source_file.c: At top level:
source_file.c:10:3: error: expected identifier or ‘(’ before ‘return’
 } return 0;
   ^