C語言中的time：
代碼如下：
#include<stdio.h>
#include<time.h>
int main()
{
time_t timep;
time(&timep);
printf("%d\n",gmtime(&timep));
printf("%s\n",asctime(gmtime(&timep)));
printf("%s\n",ctime(&timep));
return 0;
} 數(shù)據(jù)字節(jié)數(shù)輸出：
代碼如下：
#include<stdio.h>
int main()
{
printf("char %d\n",sizeof(char));
printf("int %d\n",sizeof(int));
printf("short int %d\n",sizeof(short int));
printf("long int %d\n",sizeof(long int));
printf("float %d\n",sizeof(float));
printf("double %d\n",sizeof(double));
return 0;
}
printf輸出格式：
代碼如下：
#include<cstdio>
int main()
{
//for int
int i=30122121;
long i2=309095024;
short i3=30;
unsigned i4=2123453;
printf("%d,%o,%x,%X,%ld,%hd,%u\n",i,i,i,i,i2,i3,i4);//如果是：%l,%h，則輸不出結(jié)果
printf("%d,%ld\n",i,i2);//試驗(yàn)不出%ld和%d之間的差別，因?yàn)閘ong是4bytes
printf("%hd,%hd\n\n\n",i,i3);//試驗(yàn)了%hd和%d之間的差別，因?yàn)閟hort是2bytes
//for string and char
char ch1='d';
unsigned char ch2=160;
char *str="Hello everyone!";
printf("%c,%u,%s\n\n\n",ch1,ch2,str);//unsigned char超過128的沒有字符對(duì)應(yīng)
//for float and double,unsigned and signed can not be used with double and float
float fl=2.566545445F;//or 2.566545445f
double dl=265.5651445;
long double dl2=2.5654441454;
//%g沒有e格式，默認(rèn)6位包括小數(shù)點(diǎn)前面的數(shù),
//%f沒有e格式，默認(rèn)6位僅只小數(shù)點(diǎn)后面包含6位
//%e采用e格式，默認(rèn)6位為轉(zhuǎn)化后的小數(shù)點(diǎn)后面的6位
printf("%f,%e,%g,%.7f\n",fl,dl,dl,dl);
printf("%f,%E,%G,%f\n",fl,dl,dl,dl);//%F is wrong
printf("%.8f,%.10e\n",fl,dl);
printf("%.8e,%.10f\n\n\n",fl,dl);
//for point
int *iP=&i;
char *iP1=new char;
void *iP2;//dangerous!
printf("%p,%p,%p\n\n\n",iP,iP1,iP2);
//其他知識(shí)：負(fù)號(hào)，表示左對(duì)齊（默認(rèn)是右對(duì)齊）；%6.3，6表示寬度，3表示精度
char *s="Hello world!";
printf(":%s: \n:%10s: \n:%.10s: \n:%-10s: \n:%.15s: \n:%-15s: \n:%15.10s: \n:%-15.10s:\n\n\n",
s,s,s,s,s,s,s,s);
double ddd=563.908556444;
printf(":%g: \n:%10g: \n:%.10g: \n:%-10g: \n:%.15g: \n:%-15g: \n:%15.10g: \n:%-15.10g:\n\n\n",
ddd,ddd,ddd,ddd,ddd,ddd,ddd,ddd);
//還有一個(gè)特殊的格式%*.* ,這兩個(gè)星號(hào)的值分別由第二個(gè)和第三個(gè)參數(shù)的值指定
printf("%.*s \n", 8, "abcdefgggggg");
printf("%*.*f \n", 3,3, 1.25456f);
return 0;
}
posted on 2010-09-14 10:06
jince 閱讀(221)
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學(xué)習(xí)到的一些小知識(shí)