Type Conversion

Rules for Type Conversion:

• If you assign a variable of a smaller type to one of a larger type, the value is converted to that larger type and no information is lost.
• If you assign a variable of a larger type to one of a smaller type, the value is truncated and, if the larger value is greater than the smaller type can contain, the demotion includes truncation of the excess data.

long mylong;

char mychar:

short int myint;

float myfloat = 7e4; //Is that an error? Did you mean 0x7e4? No, it’s the exponential format and means 7 times 10 to the 4^th power.

mychar =myint = mylong = myfloat;

You will get a compiler warning about moving a float into a long.

You will lose information when the value 70000 is moved into the 16 bit width of the short int. [short can hold numbers up to 65536, maximum.

mychar gets the value “p” [01110000] Hex 70

myint gets 4464 [00010001][01110000] Hex 1170

mylong gets 70000 [00000000][00000001][00010001][0111000] Hex 11170

You can clearly see that the higher order bytes are dropped as the data is placed in ever smaller containers.

An explicit typecast can eliminate a compiler warning. See Chapter 20, Typecasts.