memset is generally used as an initialization function. The function is to set all the contents of a certain memory to a certain value.
Format: start pointer, set initial value, length
memset(buffer,0,sizeof(int)*10);//在buffer处初始化10个0
memcpy is used to copy several bytes from the start of the source memory address to the target memory address.
Format: return pointer, source pointer, length
memcpy(dst, src, strlen(src)+1);
strlen is a function to calculate the length of a string. The number of characters from any location in the memory to'\0' is generally 1 less than that obtained by sizeof.
Format: String pointer
strlen(str);
strcpy is a string copy function, which copies the string containing the'\0' terminator to another address space.
Format: return pointer, source pointer
strcpy(dst,src);