8/16位系统
1. int(2个字节)-(2^15-1)~(2^15-1),即-32767~32767,数量级3*10^4
2. unsigned int(2个字节) 0~(2^16-1),即0~65535,数量级6*10^4.
3. long int(4字节):-(2^31-1)~(2^31-1),即-2147483647 ~2147483647,数量级:2*10^9.
4. unsigned long int(4字节):0~(2^32-1),即0 ~ 4294967295,数量级:4*10^9.
32/64位系统
1. int(4字节):-(2^31-1)~(2^31-1),即-2147483647 ~2147483647,2*10^9.
2. unsigned int(4字节):0~(2^32-1),即0 ~ 4294967295,4*10^9.
3. long int(8字节):-(2^63-1)~(2^63-1),即 -9223372036854775807~9223372036854775807, 9*10^18.
4. long long int(8字节):-(2^63-1)~(2^63-1),即 -9223372036854775807~9223372036854775807,9*10^18
5. unsigned long long int(8字节):0~(2^64-1),即 0~18446744073709551615,10^19
double 10^15