c++进制转换（C++ decimal conversion）.docVIP

c++进制转换（C++ decimal conversion） Eight, sixteen, convert hexadecimal number to a decimal number The binary number is converted to decimal number The zeroth bit binary number is 0 times weight of 2, first of the weight is 1 times 2...... So, there is a binary number: converted to 10 binary: The following is the upright:decimalize Zeroth 0 * 20 = 0 First 0 * 21 = 0 Second 1 * 22 = 4 Third 0 * 23 = 0 Fourth 0 * 24 = 0 Fifth 1 * 25 = 32 Sixth 1 * 26 = 64 Seventh * 27 = 0 + 0 --------------------------- One hundred Use transverse calculation: 0 * 20 + 0 * 21 + 1 * 22 + 1 * 23 + 0 * 24 + 1 * 25 + 1 * 26 + 0 * 27 = 100 How much is 0 multiplied by 0, so we can also skip the value of 0 bits: 1 * 22 + 1 * 23 + 1 * 25 + 1 * 26 = 100 Octal number is converted to decimal number Octal is every 8 into 1. Octal number expression of a number by 0 to 7 this Bashulai. Octal number zeroth weight is 0 times 8, first weight is 1 times 8, second weight is 2 times 8...... So, with an octal number: 1507, to convert to decimal: With the vertical representation: 1507 decimalize. Zeroth 7 * 80 = 7 First 0 * 81 = 0 Second 5 * 82 = 320 Third 1 * 83 = 512 -------------------------- Eight hundred and thirty-nine Similarly, we can also be used directly to calculate the: 7 * 80 + 0 * 81 + 5 * 82 + 1 * 83 = 839 As a result, 1507 octal number into a decimal number 839 The expression method of the octal number C, C++ language, how to express an octal number? If the number is 876, we can conclude that it is not an octal number, octal number is not possible because more than 7 of the digital Arabia. But if the number is 123, 567, or then it is an octal number or 10 hexadecimal number, are likely to. So, C, C++, if a number to indicate that it uses octal, must be in front of it with a 0, such as 123 is a decimal, but 0123 said the octal. This is an octal number in C and C++ expression method. The expression of C and C++ methods do not provide a binary number so here the octal