c++怎样编写将16进制的数转为10进制的数

c++怎样编写将16进制的数转为10进制的数……用函数怎么编写？16进制是随便输入的，用函数调用编写

#include<iostream.h>
#include<string.h>
#include<math.h>
void change(char *nu)
{
int i,l,j,sum=0;
l=strlen(nu);
for(i=l-1,j=0;i>=0;i--,j++)
{
if(nu[i]>='0'&&nu[i]<='9')
sum+=(nu[i]-48)*pow(16,j);
if(nu[i]>='a'&&nu[i]<='f')
sum+=(nu[i]-87)*pow(16,j);
if(nu[i]>='A'&&nu[i]<='F')
sum+=(nu[i]-55)*pow(16,j);
}
cout<<"转为十进制数为:"<<sum<<endl;
}
void main()
{
char num[10];
cin>>num;
cout<<"十六进制数:"<<num<<endl;
change(num);
}

#include <iostream> using namespace std; #define MAX_NUM 100 int q(int n) ////////////求权 { int result(1); if(n==0) return 1; else { for(int i=0;i<n;i++) { result*=16; } return result; } } int translate(char* c) { int result(0),tmp(0); int count(0); for(int i=0;c[i]!='\0';i++) count=i; for(int i=0;i<count+1;i++) { if(c[i]>='0' && c[i]<='9') result+=(int(c[i])-48)*q(count-i); else if(c[i]>='a' && c[i]<='f') result+=(int(c[i])-87)*q(count-i); else if(c[i]>='A' && c[i]<='F') result+=(int(c[i])-55)*q(count-i); else return -1; } return result; } int main() { char a[100]={' '}; cin>>a; cout<<translate(a)<<endl; }

在机器中所有数据都是十六进制形式的. printf sprintf 这两个函数提供此类型的转换. 建议楼主查看这两个函数的用法.

建议用栈来处理 我曾经做过八进制转十进制的，你可以参考一下： #include<stdio.h> #include<stdlib.h> #define OK 1 #define STACK_INIT_SIZE 100 #define OVERFLOW -2 #define STACKINCREMENT 10 #define ERROR 0 typedef int status; typedef int elemtype; typedef struct { elemtype *base; elemtype *top; int stacksize; }SqStack; status InitStack(SqStack *S) { S->base=(elemtype*)malloc(STACK_INIT_SIZE*sizeof(elemtype)); if(!S->base) return OVERFLOW; S->top=S->base; S->stacksize=STACK_INIT_SIZE; return OK; } status push(SqStack *S,elemtype e) { if(S->top-S->base>=S->stacksize) { S->base=(elemtype*)realloc(S->base,(S->stacksize+STACKINCREMENT)*sizeof(elemtype)); if(!S->base)return OVERFLOW; S->top=S->base+S->stacksize; S->stacksize+=STACKINCREMENT; } *S->top++=e; //printf("%d ",*(S->top-1)); return OK; } status pop(SqStack *S,elemtype *e) { if(S->top==S->base) return ERROR; *e=*--S->top; return OK; } void main() { SqStack S; elemtype n; elemtype e; InitStack(&S); printf("请输入要转换的十进制数："); scanf("%d",&n); while(n) { push(&S,n%8); n=n/8; } printf("\n"); printf("转换后的八进制数："); while(S.base!=S.top) { pop(&S,&e); printf("%d",e); } printf("\n"); }