1
C C
C
C
C
1.1.
hello, world
C “hello, world
#include
main()
{
printf("hello, world\n");
}
UNIX
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“.c hello.c
cc hello.c
a.out
a.out
a.out
hello, world
#include
main()
{
printf("hello, world\n");
}
main
main
main printf
\n
C
C
C Fortran Pascal
main main
—— main
main
main
#include
C
7 B
main
()
{} main
printf("hello, world\n");
"hello,
world\n" printf printf
"hello, world\n"
printf
C \n
\n
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printf \n \n
printf("hello, world
");
C
printf
#include
main()
{
printf("hello, ");
printf("world");
printf("\n");
}
\n \n
C \t
\b \"\\2.3
11
“hello, world
12
printf \c c
1.2.
=(5/9)(32)
1
20
40
60
80
100
120
140
160
180
200
220
240
260
280
300
17
6
4
15
26
37
48
60
71
82
93
104
115
126
137
148
main “hello, world
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*/
#include
/* fahr=020… 300
main()
{
int fahr, celsius;
int lower, upper, step;
lower = 0; /* */
upper = 300; /* */
step = 20; /* */
fahr = lower;
while (fahr <= upper) {
celsius = 5 * (fahr32) / 9;
printf("%d\t%d\n", fahr, celsius);
fahr = fahr + step;
}
}
/* fahr=020… 300
*/
/**/
C
int fahr, celsius;
int lower, upper, step;
int float
int float int
16 3276832767 32 int float
32 6 10381038
int float C
char
short
long
double
——
4
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lower = 0;
upper = 300;
step = 20;
fahr = lower;
while
while (fahr <= upper) {
...
}
while
(fahr<=upper) 3
(fahr>upper)
while
while
while (i < j)
i = 2 * i;
while
C
celsius = 5 * (fahr 32) / 9
celsius
5 9 5 / 9 C
5 9
5 / 9 0 0
printf printf
7 %
……
%d
printf(" %d\t%d\n", fahr, celsius);
fahr celsius \t
printf %……
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printf C C
printf C
ANSI printf
C 7
7
7.4 scanf scanf printf
printf
%d
printf(" %3d %6d\n", fahr, celsius);
fahr celsius fahr 3 celsius 6
0 17
20 6
40 4
60 15
80 26
100 37
...
017.817
#include
/* print FahrenheitCelsius table
for fahr = 0, 20, ..., 300; floatingpoint version */
main()
{
float fahr, celsius;
float lower, upper, step;
lower = 0; /* lower limit of temperatuire scale */
upper = 300; /* upper limit */
step = 20; /* step size */
fahr = lower;
while (fahr <= upper) {
celsius = (5.0/9.0) * (fahr32.0);
printf("%3.0f %6.1f\n", fahr, celsius);
fahr = fahr + step;
}
}
fahr celsius float
5 / 9
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0
5.0 / 9.0
fahr – 32 32
2
fahr = lower;
while (fahr <= upper)
int float
printf %3.0f fahr 3
%6.1f celsius 6
1
0 17.8
20 6.7
40 4.4
...
%6f 6 %.2f
%f
%d
%6d
%f
%6f
%.2f
%6.2f
printf %o %x %c
6
6
6
%s %%%
13
14
1.3.
for
#include
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/*—*/
main()
{
int fahr;
for (fahr = 0; fahr <= 300; fahr = fahr + 20)
printf("%3d %6.1f\n", fahr, (5.0/9.0)*(fahr32));
}
int fahr for
printf
C
printf
%6.1f
for while for
while for 3
fahr = 0
fahr <= 300
true
printf
fahr = fahr + 20
fahr faise
while for
whi1e for
for
while
15
300 0
1.4.
30020
#define
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