View Compilation Error

0_0_18060485_30563.cpp: In function 'int main()':
0_0_18060485_30563.cpp:35:73: error: 'sort' was not declared in this scope
   for (i = 0; i < m && scanf("%d%d", &l, &r); i++, sort(a + l - 1, a + r));
                                                                         ^