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//转二进制 char *ConvertTo2String( long number); //转十六进制 char *ConvertTo16String( long number); |
思路:
转换二进制很简单,二步操作即可完成,
1:循环对数字1左移31-i(i={0,31})位(从高位开始的),再与把number作位与操作,
2:再把刚才的结果通过右移31-i (i={0,31}) 位得出每一位是否为0还是1,
这样就得到了每一位的二进制位,再把这些二进制位拼成字符串就OK了!
char *ConvertTo2String(long number)
{
char *output = NULL;
output = (char*)malloc(33);//include '\0'
int i = 0;
for(;i<32;i++)
{
output[i] = number & (1<<31-i);
output[i] = output[i] >> 31-i;
output[i] = (output[i] == 0) ? '0':'1';
}
output[i] = '\0';
return output
}
转换十六进制麻烦一点,要考虑字母的情况,
char * ConvertTo16String(long number)
{
char *output= NULL;
char *temp = NULL;
output= (char*)malloc(11);
output[0] = '0';
output[1] = 'x';
output[10] = '\0';
temp = output+ 2;
for(int i = 0; i<8; i++)
{
temp[i] = (char)(number<< 4 * i >> 28); //先左移4*i,再右移28,每一次处理4位
temp[i] = temp[i]>=0 ? temp[i] : temp[i]+16; //为转换为A~F的字母作准备
temp[i] = temp[i] < 10 ? temp[i]+48 : temp[i]+55; //转字母
}
return output;
}
#include<stdio.h>
long fun(char*s);
#define N 50
void main()
{
long m;
char s[N];
printf("输入十六进制数: ");
scanf("%s",s);
m=fun(s);
printf("%ld",m);
}
long fun(char*s)
{
int i,t;
long sum=0;
for(i=0;s[i];i++)
{
if(s[i]<='9')t=s[i]-'0';
else t=s[i]-'a'+10;
sum=sum*16+t;
}
return sum;
}