stdlib.h
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stdlib.h
<![CDATA[
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
double ddt;
char ss[] = "78999.8";
ddt = atof(ss);
printf("%f\n", ddt);
return 0;
}
/*
运行结果
无<stdlib.h>时
4230120.000000
有<stdlib.h>时
78999.800000
*/
]]>
stdlib.h,srand
<![CDATA[
#include <stdio.h>
#include <stdlib.h>
int main(void)
{
unsigned sd;
printf("Please input one number:");
scanf("%d", &sd);
srand(sd);
printf("sd=%d",sd);
return 0;
}
/*
运行结果
Please input one number:44
sd=44
*/
]]>
stdlib.h,abort
<![CDATA[
#include <stdio.h>
#include <stdlib.h> /* for abort */
#include <signal.h>
int mystatus;
void myhandle(int sig)
{
printf("Signal %d started.\n", sig);
printf("status=%d, the program stopped.\n", mystatus);
printf("Please ask question with the NO.\n");
}
int main(void)
{
signal(SIGABRT, myhandle);
mystatus = 1234;
puts("----abort Front");
abort();
puts("----abort After");
return 0;
}
/*
运行结果
----abort Front
abnormal program termination
Signal 22 started.
status=1234, the program stopped.
Please ask question with the NO.BUFSIZ=512
abcdefghijABCDEFGHIJ
*/
]]>
stdlib.h,malloc,realloc
<![CDATA[
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void memput(char *p, int n)
{
int i;
for (i=0; i<n; i++)
putchar(*p++);
putchar('\n');
}
int main(void)
{
char *p1, *p2, *p3;
p1 = (char *)malloc(100);
strcpy(p1, "abcdefghij");
memput(p1, 10);
p2 = (char *)realloc(p1, 200);
memput(p2, 10);
p3 = (char *)realloc(p2, 5);
memput(p3, 6);
return 0;
}
/*
运行结果
abcdefghij
abcdefghij
abcdef
*/
]]>
stdlib.h,rand
<![CDATA[
#include <stdio.h>
#include <stdlib.h>
#define RAND_MAX 0x7fff;
main(void)
{
double rand1;
rand1 = rand();
printf ("rand1=%f\n",rand1);
return 0;
}
/*
运行结果
rand1=41.000000
*/
/* Maximum value that can be returned by the rand function. */
#define RAND_MAX 0x7fff
#define RAND_MAX 0x7fff;
test090302.c(4) : warning C4005: 'RAND_MAX' : ﾏｸﾛが再定義されました。
C:\Program Files\Microsoft Visual Studio\VC98\include\stdlib.h(129) : 'R
AND_MAX' の前の定義を確認してください
Microsoft (R) Incremental Linker Version 6.00.8168
Copyright (C) Microsoft Corp 1992-1998. All rights reserved.
]]>
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