View Compilation Error

0_0_35543127_17409.cpp: In function 'int main()':
0_0_35543127_17409.cpp:15:21: error: 'strlen' was not declared in this scope
    if (n >= strlen(c) - 1)
                     ^
0_0_35543127_17409.cpp:22:23: error: 'strlen' was not declared in this scope
      if (n >= strlen(c) - 1)
                       ^