Question

请大神帮我看看，这段程序哪里出错了？？谢谢！

#include<iostream>
using namespace std;
char *deletechar(char *a)
{
int len=strlen(a);
char *b;int k=0;
for(int i=0;i<len;i++)
{
if(a[i]>='0' && a[i]<='9')
b[k++]=a[i];
}
return b;
}
int main()
{
char a[10]="asd236f33";
char *c=deletechar(a);
for(int i=0;i<strlen(c);i++)
cout<<c[i]<<" ";
cout<<endl;
return 0;
}

Answer 1

char *deletechar(char *a)
{
int len=strlen(a);
char *b;int k=0;
for(int i=0;i<len;i++)
{
if(a[i]>='0' && a[i]<='9')
b[k++]=a[i];
}
return b;
}
上面函数中char*b没有申请空间，造成b[k++]访问非法内存出错

追问

你把你改后的程序粘贴出来呢，谢谢！

追答

#include
using namespace std;
char *deletechar(char *a)
{
assert(a != 0);
int len=strlen(a);
char *b = new char[len + 1];
int k=0;
for(int i=0;i='0' && a[i]<='9')
b[k++]=a[i];
}
b[k] = '\0';
return b;
}
int main()
{
char a[10]="asd236f33";
char *c=deletechar(a);
for(int i=0;i<strlen(c);i++)
cout<<c[i]<<" ";
delete [] c;
cout<<endl;
return 0;
}

Answer 2

#include<iostream>
using namespace std;
char *deletechar(char *a)
{
int len=strlen(a);
char *b= new char[len] ;
int k=0;
for(int i=0;i<len;i++)
{
if(a[i]>='0' && a[i]<='9')
b[k++]=a[i];
}
return b;
}
int _tmain(int argc, _TCHAR* argv[])
{

char a[10]="asd236f33";
char *c=deletechar(a);
for( int i=0;i<(int)strlen(c);i++)
cout<<c[i]<<" ";
cout<<endl;
getchar();
return 0;
}

Answer 3

#include<iostream>
using namespace std;
char *deletechar(char *a)
{
int len=strlen(a);
char *b=new char();
int k=0;
for(int i=0;i<len;i++)
{
 if(a[i]>='0' && a[i]<='9')
 {
  b[k]=a[i];
 k++;
 }
}
return b;
}
int main()
{
char a[10]="asd236f33";
char *c=deletechar(a);
for(int i=0;i<strlen(c);i++)
  cout<<c[i]<<"  ";
 cout<<endl;
 return 0;
}

修改后代码如上

Answer 4

我就看看。学习了