View Compilation Error

0_0_16430287_19429.cpp: In function 'int main()':
0_0_16430287_19429.cpp:31:20: error: 'memset' was not declared in this scope
    memset(c, 0, n+1);
                    ^
0_0_16430287_19429.cpp:72:21: error: 'memset' was not declared in this scope
     memset(c, 0, n+1);
                     ^