Chapter One
1.2 Program Example
I. Hello World Program:
Form 1:
#include
int main ()
{std :: cout << "Hello, World! / N;
}
Form 2:
#include
Using namespace std; // Using namespace
int main ()
{
Cout << "Hello, World! / N;
}
Related knowledge: 1. Preprocessing instructions
2. Space
.1.3 Output operator
ENDL flag effect: Print the cursor to the next row and clear the buffer
1.4 characters and text
Character is stored in an integer in the computer
Space character indicates: ''
1.6 program tag
When the compiler is inspected, the omissible tag is discovered when checking the next tag.
1.8 objects, variables and constants
Object is a region connected in memory
The size of the object is determined by the compiler. EG, GNU C , INT size is 4, in Borland C , INT size is 2
Usually habits with uppercase letters to represent constant markers
Constants must be initialized when declaring
Review questions:
The role of the statement: tell the type and variable name represented by the compiler
The role of pretreatment of pseudo-instructions: including the contents of the header files
% Is "Search" operator
1.15 identify the character of the ASCII code to 100: Cont << "char (100)" << char (100) << endl;
1,18 integer overflows Different from floating point number: Integer "Roll" is negative, floating point numbers are set to infinite constants.
1.19 1.20 Distinguish between runtime errors and compile errors: EG. Overflow and except 0 .....
exercise
1.1 minus 1 different writing method from N: n = N-1; N - N- = 1;
1.5 Reduce the variable N to 1 after 1, add to Total: Total = Total - -N; => Total = - -N
1.13 causes short variables that overflow: short = 0; short- = 1000; Short - = 2000; .......
