标C函数itoa实现的源代码[增强版]

本人参考的是

http://topic.youkuaiyun.com/u/20080131/09/e2ce083e-e54a-4b6e-a98b-7bfe82c3117e.html?seed=1462871643

但是他没有考虑负数和零的问题！这里特别改进一下。char *itoaw(int num, char *str, int radix) { if(num==0) { str[0]='0';str[1]='/0'; return str; } char string[] = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; char* ptr = str; int i; int j; int value=num; if(num<0) num=-num; while (num>=radix) { *ptr++ = string[num % radix]; num /= radix; } if (num) { *ptr++ = string[num]; *ptr = '/0'; } int n=j= ptr-str-1; for (i=0; i <(ptr - str) / 2; i++) { int temp = str[i]; str[i] = str[j]; str[j--] = temp; } if(value<0) { for(j=n;j>=0;--j) str[j+1]=str[j]; str[0]='-'; } str[n+2]='/0'; return str; }