View Compilation Error

0_0_22012118_12062.cpp: In function 'int main()':
0_0_22012118_12062.cpp:18:24: error: 'memset' was not declared in this scope
 memset(dp,-1,sizeof(dp));
                        ^
0_0_22012118_12062.cpp: In function 'int main()':
0_0_22012118_12062.cpp:65:5: error: redefinition of 'int main()'
 int main()
     ^
0_0_22012118_12062.cpp:4:5: note: 'int main()' previously defined here
 int main()
     ^
0_0_22012118_12062.cpp:76:33: error: 'strcmp' was not declared in this scope
             if(strcmp(s[i-1],"@")==0)
                                 ^
0_0_22012118_12062.cpp:80:33: error: 'memset' was not declared in this scope
         memset(len,0,sizeof(len));
                                 ^
0_0_22012118_12062.cpp:89:33: error: 'strlen' was not declared in this scope
             int temp=strlen(s[i]);
                                 ^
0_0_22012118_12062.cpp:116:33: error: 'strlen' was not declared in this scope
             int temp=strlen(s[i]);
                                 ^