. -. , , .
:
- ;
- , ;
- , .
, , . . , .
C++ . C++ , , . . , , , , , , .
C++
() , . :
- int ();
- char ();
- wchar_t ( );
- bool ();
- float ();
- double ( ).
(), . , , .
, :
- short ();
- long ();
- signed ();
- unsigned ().
(int)
int , . 16- 2 , 32- 4 .
short , 2 . long , 4 . , 16- int short int, 32- int long int.
. signed (0 , 1 ). unsigned , . , int . IBM PC- .
|
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, signed .
, , . - , L, l (long) U, u (unsigned). , 32L long 4 . L U , , 0x22UL 05Lu.
short int, long int, signed int unsigned int short, long, signed unsigned .
(char)
, , . , 1 . char, , . -128 127. unsigned 255. 256- ASCII. char , .
(wchar_t)
wchar_t , 1 , , Unicode. ; , short. wchar_t L, , LGates.
(bool)
true false, . false 0 (). true. true 1.
(float, double long double)
C++ : float, double long double.
, . . IBM PC- float 4 , , 8 23 . , 1.0, 2.0. 1, .
double, 8 , 11 52 . , . , , float long int, - .
long double , 10 .
double. F, f (float) L, l (long). , 2E+6L long double, 1.82f float.
int. sizeof, . , MS-DOS sizeof (int) 2, Windows 98 OS/2 4.
|
|
|
ANSI , , :
sizeof(float) ≤ slzeof(double) ≤ sizeof(long double)
sizeof(char) ≤ slzeof(short) ≤ sizeof(int) ≤ sizeof(long)
<limits.h> (<climits>), <float.h> (<cfloat>), numeric_limits
void
, void, . , , , .
C++ IBM PC-
Q: IBM PC- ?
A: IBM PC- (. IBM PC compatible) , IBM PC, XT AT. IBM PC- , Intel 8086 (, , Intel 8086). .
, , , , . - , .
| () | ||
| bool | true false | |
| signed char | -128 127 | |
| unsigned char | 0 255 | |
| signed short int | -32 768 32 767 | |
| unsigned short int | 0 65 535 | |
| signed long int | -2 147 483 648 2 147 483 647 | |
| unsigned long int | 0 4 294 967 295 | |
| float | 3.4e-38 3.4e+38 | |
| double | 1.7e-308 1.7C+308 | |
| long double | 3.4e-4932 3.4e+4932 |
.
2: C. . .
1) C
, .
, . . , , , - , . , , , " " , . , .
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;
;
;
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( ), .
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. , , . , , . , , , (, , ..).
:
1. ( );
2. ;
3. ( ).
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18
1: C.
. -. , .
-, FILE, stdio.h. FILE .
fopen(), FILE, .
FILE *fopen(name, type);
name ( ),
type - , :
"r" ( );
"w" ; , ;
"a" ( ); , ;
"r+" ( );
"w+" ; , ;
"a+" , , .
- . , NULL.
fclose() , fopen() . fclose().
: 0, ; EOF, .
#include <stdio.h>
int main() {
FILE *fp;
char name[]="my.txt";
if(fp = fopen(name, "r")!=NULL) { // ?
... //
} else printf(" ");
fclose(fp);
return 0;
}
:
char fgetc();
FILE. . , EOF.
:
fputc(,);
FILE. .
fscanf() fprintf() scanf() printf(), , .
fscanf(, "", );
fprintf(, "", );
fgets() fputs() - , gets() puts() .
fgets(,,);
, '\n', , EOF . - '\0'. .
fputs(,);
. - .
s1.txt. s1.txt, 3 s2.txt.
#include <stdio.h>
#include <stdlib.h>
int main() {
FILE *S1, *S2;
int x, y;
system("chcp 1251");
system("cls");
printf(" : ");
scanf("%d", &x);
S1 = fopen("S1.txt", "w");
fprintf(S1, "%d", x);
fclose(S1);
S1 = fopen("S1.txt", "r");
S2 = fopen("S2.txt", "w");
fscanf(S1, "%d", &y);
y += 3;
fclose(S1);
fprintf(S2, "%d\n", y);
fclose(S2);
return 0;
}
- 2
19
1: C.
(enum), .
?
| enum <> { < 1>, < 2>, ... < N> }; // ;! |
?
| #include <conio.h> #include <stdio.h> enum Gender { MALE, FEMALE }; void main() { enum Gender a, b; a = MALE; b = FEMALE; printf("a = %d\n", a); printf("b = %d\n", b); getch(); } |
Gender. enum Gender MALE FEMALE.
|
|
|
, 0, 1, 2 .. :
?
| #include <conio.h> #include <stdio.h> enum Token { SYMBOL, //0 NUMBER, //1 EXPRESSION = 0, //0 OPERATOR, //1 UNDEFINED //2 }; void main() { enum Token a, b, c, d, e; a = SYMBOL; b = NUMBER; c = EXPRESSION; d = OPERATOR; e = UNDEFINED; printf("a = %d\n", a); printf("b = %d\n", b); printf("c = %d\n", c); printf("d = %d\n", d); printf("e = %d\n", e); getch(); } |
0 1 0 1 2. , SYMBOL EXPRESSION, NUMBER OPERATOR.
?
| enum Token { SYMBOL, //0 NUMBER, //1 EXPRESSION = 10, //10 OPERATOR, //11 UNDEFINED //12 }; |
SYMBOL 0, NUMBER 1, EXPRESSION 10, OPERATOR 11, UNDEFINED 12.
, , . , switch.
, Token . Token . , .
. - , .
?
| #include <conio.h> #include <stdio.h> #include <stdlib.h> static char *ErrorNames[] = { "Index Out Of Bounds", "Stack Overflow", "Stack Underflow", "Out of Memory" }; enum Errors { INDEX_OUT_OF_BOUNDS = 1, STACK_OVERFLOW, STACK_UNDERFLOW, OUT_OF_MEMORY }; void main() { // printf(ErrorNames[INDEX_OUT_OF_BOUNDS-1]); exit(INDEX_OUT_OF_BOUNDS); } |
, . exit(N) , , 0 - . .
. , enum , . , .
?
| typedef enum enumName { FIELD1, FIELD2 } Name; |
?
| typedef enum Bool { FALSE, TRUE } Bool; |
2:/ C++.
++, , -.
stdio.h.
++ - iostream, - :
#include <iostream>
iostream :
cin (stdin )
cout (stdout )
cerr (stderr )
Microsoft Visual Studio :
using namespace std;
- :
>>
<<
cout << ;
:
cout << n;
:
cout << '1' << '2' <<... << ' n';
int n;
char j;
cin >> n >> j;
cout << " n " << n << "j=" << j;
cin >> ;
, , :
int n;
cin >> n;
:
cin >> 1 >> 2 >>...>> n;
(, \n, \t).
int n;
char j;
cin >> n >> j;
. cin , .
#include <iostream>
using namespace std;
int main() {
char s[80];
cin >> s;
cout << s << endl;
system("pause");
return 0;
}
getline():
#include <iostream>
using namespace std;
int main() {
char s[80];
cin.getline(s,80);
cout << s << endl;
system("pause");
return 0;
}
- (<<, >>).
++ . :
| endl | '\n' |
| dec | 10- |
| oct | 8- |
| hex | 16- |
| setbase | |
| width() | |
| fill('') | |
| precision() | ( ) fixed |
| fixed | , |
| showpos | + |
| scientific | |
| get() | |
| getline(, ) | . |
- C++
#include <iostream>
using namespace std;
int main() {
int n;
cout << " n:";
cin >> n;
cout << " n : " << n << endl;
cin.get(); cin.get();
return 0;
}
,
#include <stdio.h>
int main() {
int n;
printf(" n:");
scanf("%d",&n);
printf(" n : %d\n",n);
getchar(); getchar();
return 0;
}
#include <iostream>
using namespace std;
int main()
{
double a = -112.234;
double b = 4.3981;
int c = 18;
cout << endl << "double number:" << endl;
cout <<"width(10)" << endl;
cout.width(10);
cout << a << endl << b << endl;
cout <<"fill('0')" << endl;
cout.fill('0');
cout.width(10);
cout << a << endl << b << endl;
cout.precision(5);
cout <<"precision(5)" << endl << a << endl << b << endl;
cout << "fixed" << endl << fixed << a << endl << b << endl;
cout << "showpos" << endl << showpos << a << endl << b << endl;
cout << "scientific" <<endl << scientific << a << endl << b << endl;
cout << endl << "int number:" << endl;
cout << showbase << hex << c <<" " << showbase << oct << c << " ";
cout << showbase << dec << c << endl;
cin.get();
return 0;
}
: t∈[0;3] 0,5 y=cos(t).
#include <iostream>
using namespace std;
int main() {
cout<<fixed;
for (double t = 0; t <= 3; t += 0.5) {
cout.width(3);
cout.precision(1);
cout << t;
cout.width(8);
cout.precision(3);
cout << cos(t) << endl;
}
system("pause");
return 0;
}
20
1: . .
, . . .
(). #. , , .
#include
#define ()
#undef
#if
#ifdef
#ifndef
#else
#elif , else if
#endif
#line
#error
#pragma , .
#include
#include . , . , . , .
#include <stdio.h>
#include "func.c"
#define
#define .
define
. #define , , , . , , .
#include <stdio.h>
#define A 3
int main(){
printf("%d + %d = %d", A, A, A+A); // 3 + 3 = 6
getchar();
return 0;
}
. :
U u (unsigned);
F ( f) float;
L/span> ( l) 8 (long int);
L/span> ( l) long double
#define A 280U // unsigned int
#define B 280LU // unsigned long int
#define C 280 // int (long int)
#define D 280L // long int
#define K 28.0 // double
#define L 28.0F // float
#define M 28.0L // long double
, , . , .
(1,..., n)
, .
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define PI 3.14159265
#define SIN(x) sin(PI*x/180)
int main() {
int c;
system("chcp 1251");
system("cls");
printf(" : ");
scanf("%d", &c);
printf("sin(%d)=%lf", c, SIN(c));
getchar(); getchar();
return 0;
}
, . , , . 1 , , .
#undef.
,
#include <stdio.h>
#define sum(A,B) A+B
int main(){
int a,b,c,d;
a=3; b=5;
c = (a + b)*2; // c = (a + b)*2
d = sum(a, b) * 2; // d = a + b*2;
printf(" a = %d\n b = %d\n", a, b);
printf(" c = %d \n d = %d \n", c, d);
getchar();
return 0;
}
:
#if #ifdef/#ifndef #elif, #else #endif . #if , , #if. :
