/*prog14.c
, */
#include <stdio.h>
main()
{
float x, s = 0; /* s , , ; x , */
int flag; /* flag , scanf */
flag = scanf ("%f", &x);
/* , ; , scanf EOF, stdio.h*/
while (flag!= EOF)
{
s = s + x;
flag = scanf ("%f", &x);
}
printf ( %f\n, s);
return 0;
}
mydata.txt, :
121.45 12.78 151.11 777.76
prog14.c , :
prog14.exe < mydata.txt
< , prog14.exe mydata.txt. , mydata.txt.
:
(8.1) , , ;
(8.2) , , ;
(8.3) , , ;
(8.4) , , ;
(8.5) , , ;
(8.6) , , ;
(8.7) , , ;
(8.8) n, 1, 2,..., n ( n! - n );
(8.9) , ;
(8.10) , , ;
(8.11) , , ;
(8.12) , , ;
9.
char (character - ). ASCII-, , ( ). %.
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|
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/*prog15.c*/
#include<stdio.h>
main()
{
char x = A, y = 97;
printf ( %d, %c \n %d, % \n, x, x, y, y);
return 0;
}
, ASCII- 65, ASCII- 97 .
, int char, , . .
sizeof (_)
, .
/*prog16.c*/
#include<stdio.h>
main()
{
int x = 97;
char y = 97;
printf ( int %d, %d char %d, %d , x, sizeof(x), y, sizeof(y));
return 0;
}
printf - x, sizeof(x), y, sizeof(y) .
, char. ( ), . - - %s. .
/*prog17.c*/
#include<stdio.h>
main()
{
char str[20] = I am a student;
str[6] = 0;
printf(%s\n, str);
return 0;
}
, str. char, str . : str[6] = 0 str 6 0. : str , char. ; 0, 19. I am a student 11 14 , , , 15 , . 6 0, , . prog16.c, , 6 : I am a.
. str , .. str str[0].
, *.
/*prog18.c*/
#include<stdio.h>
main()
{
char *str = I am a student;
str[7]=S;
printf(%s \n, str);
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|
return 0;
}
I am a Student. ,
char str[20];
char *str;
. , , .
prog17.c prog18.c , . = , . :
scanf(%s, str);
/*prog19.c*/
/* ( ), */
#include <stdio.h>
#define N 1000
main()
{
char str[ N ];
scanf (%s, str);
printf(%s \n, str);
return 0;
}
str prog19 . , . , , define, .
/*prog20.c*/
/* ( ), */
#include<stdio.h>
#define N 1000
main()
{
char c, str[ N ]; /* str , , c */
unsigned int i; /* i */
scanf (%s, str);
i = 0;
c = str[ i ]; /* c*/
while (c!= 0)
{
i++;
c = str [ i ];
}
/* i , ; , , i , */
printf(%u \n, i);
return 0;
}
, :
<9.1> , , ( prog20.c), while for;
<9.2> ( ) ;
<9.3> ( ), ;
<9.4> ( ), , , :
: aabbc,
: a a b b c;
<9.5> ( ) , , :
: aabbc,
:
a
a
b
b
c;
<9.6> ( ) , , ;
<9.7> ( ) , , ;
<9.8> , , , ;
10
, . , . :
/*prog20.c*/
#include<stdio.h>
|
|
|
main(int argc, char* argv[])
{
printf( %d \n, argc);
if (argc > 1)
printf( - %s \n, argv[ 1 ]);
else
printf ( %s \n, argv[0]);
return 0;
}
main , . argc argv. argc int, . argc , . (Tab), , . , , argc .
printf( %d \n, argc);
argc. :
prog6.c aa bb cc
argc 4.
argv char - * []:
har* argv[];
* char, argv . , , (, ), , . ([]) (*) . , argv, char* - . , argv , .. , . . argv : argv[0] - , argv [1] .., .
printf( - %s \n, argv[1]);
- argv[1].
, . if (). , , arg > 1. , , , else , . , .
printf( %s
\n, argv[0]);
.
.
, , , ( ). .
. ; 0, 1, 2,.. m * n, m , n . , i- j- a [ i ] [ j ]; m * n, i = 0, 1,.., m - 1, j = 0, 1,, n - 1. i j a [ i ] [ j ].
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|
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:
/* matrix1
1000*1000; a [ 0 ] [ 0 ], */
# include<stdio.h>
# define M 1000
# define N 1000
main()
{
int a [ M ] [ N ]; //
int i = 0, j = 0;
scanf (%d,&(a [ i ] [ j ])); // [ i ] [ j ], i = j = 0
printf ( %d\n, a [ i ] [ j ]); // [ i ] [ j ], i = j = 0
return 0;
}
# define; i, j (, ).
. matrix1.
, , . , /* */; , //, .
, , . . for.
/* matrix2
, ; (, )*/
//
# include<stdio.h>
# define M 1000
# define N 1000
main()
{
//
int a [ M ] [ N ];
int m, n, i, j;
//
scanf ( %d %d, &m, &n);
//
for (i = 0; i < m; i++)
for (j = 0; j < n; j++)
scanf ( %d, &(a [ i ] [ j ]));
//
for (j = 0; i < n; i++)
for (i = 0; j < m; i++)
printf( %d , a [ i ] [ j ]);
return 0;
}
matrix1, , 1000*1000. , m n, , , 1000. , . , m*n.
for (i = 0; i < m; i++) i 0, i < m. , , for. i 1 ( i++, ), i < m .. i < m , , for, , .
for!!!
, for, . ; , for (i = 0; i < m; i++) . , . .
, , , , 2-4 .
. matrix2
, , . , , \n
for (j = 0; j < m; j++)
{
for (i = 0; i < n; i++)
printf (%d , a [ i ] [ j ]);
printf ( \n );
}
( %d printf , ).
. .
, for . : . {}.
|
|
|
, , . , , . mydata.txt,
3 4
1 2 3 4
4 3 1 2
17 18 19 20
, . matrix2; matrix2.exe. ,
matrix2.exe < mydata.txt
< , matrix2.exe mydata.txt
. , .
. , - , , .
: m * n; .
matrix1, matrix2 . matrix3
/* matrix3
, ;
*/
//
# include<stdio.h>
# define M 1000
# define N 1000
main()
{
//
int a [ M ] [ N ];
int m, n, i, j;
int buf;
//
scanf(%d % d,&m, &n);
// ,
//
for (i = 0; i < m; i++)
for (j = 0; j < n; j++)
scanf (%d,& (a [ i ] [ j ]));
//
for (j = 0; j < n; j++)
{ buf = a [ 0 ] [ j ];
// buf
// j
a [ 0 ] [ j ] = a [ m ] [ j ];
a [ m ] [ j ] = buf;
}
// -
for (i = 0; i < m; i++)
for (j = 0; j < n; j++)
printf (%d , a [ i ] [ j ]);
return 0;
}
. matrix3, .
-. a [ i ] [ j ] a [ ] [ j ], i 0, n - 1, i 1, 1 , I .
for (j = 0; j < n; j++)
for (i = 0; = n - 1; i < ; i++, --)
{ buf = a [ i ] [ j ];
a [ i ] [ j ] = a [ ] [ j ];
a [ ] [ j ] = buf;
}
, , , ; , for i 0, - n - 1. i 1, 1 ( --, ).
. , , 1 . .
. , a b, , a b.
( ) perfnum: - - perfect number.
. , , 6 : 6 = 1 + 2+ 3. , :
a=2 b=10
perfnum.txt
6.
1
/*perfnum1.c*/
/* , */
#include <stdio.h>
main()
{
int a,b;
scanf (" a=%d b=%d", &a, &b);
printf (" a=%d b=%d\n");
return 0;
}
. :
perfnum.txt > perfnum.exe
2
/*perfnum2.c*/
/* a,b, a b*/
#include <stdio.h>
main()
{
int a,b;
int j;
scanf (" a=%d b=%d", &a, &b);
printf ("divisors of a: \n")
for (j = 1; j < a; j++)
if (a % j == 0)
printf (" %d ", j);
printf (" /n divisors of b: \n")
for (j = 1; j < b; j++)
if (b % j == 0)
printf ("%d ", j);
return 0;
}
a 1, 2,..., a-1. a j , j a, . b.
3
/*perfnum3.c*/
/* a,b, , a b*/
#include <stdio.h>
main()
{
int a, b;
int i, j, s;
scanf (" a=%d b=%d", &a, &b);
for (i = a; i <= b; i++)
{ // , a b
s = 0; // s
for (j = 1; j < i; j++)
if (i % j == 0) s+=j;
/* s i */
if (i == s)
printf ("%d ", i);
}
return 0;
}
, a b. . , , - , , -, , .. - . . , a=1, b , n. , , n, 1+2+...+n-1 : 1 n k- k-1 , k;1+2+...+n-1 = n * (n 1) / 2, , n * n .
, . '' - , .
