C++ error: heap corruption detected:after normal block(#xxx) at 0x xxxxxxxx

This error can occur when deleting or freeing a memory block whose content is longer than its size, that is memory overflow.

example 1:

      

    char*test=(char*)malloc(5);

    strcpy(test,"hello");

    free(test);

example 2:

    char*test=newchar[5];

    strcpy(test,"hello");

    delete test;