Conversion of data of types ( uint8_t, uint16_t and uint32_t ) to int32_t and viceversa

I am new to Embedded Linux platform and C++14. Need to convert different data of types ( uint8_t, uint16_t and uint32_t ) to int32_t and back to the original datatypes ( uint8_t uint16_t and uint32_t ) from int32_t. Is this possible and suggest the ways to do this