View Compilation Error

0_0_17939502_25521.cpp: In function 'int main()':
0_0_17939502_25521.cpp:21:25: error: 'memset' was not declared in this scope
   memset(dp,0,sizeof(dp));
                         ^
0_0_17939502_25521.cpp:22:7: error: 'i' was not declared in this scope
   for(i=1;i<=n;i++)
       ^
0_0_17939502_25521.cpp:28:8: error: 'j' was not declared in this scope
    for(j=w[i];j<=m;j++)
        ^