c - 使用变量将不同的字符串分配给 char 数组

Question

输入lakenum是1-5的整数。给定该整数，该函数应该分配一个名称并将字符串数组返回给主函数，但我却收到了指针错误:

error: return makes integer from pointer without a cast
error: function returns address of local variable

我使用 printf ("%s", lakenamer(lakenum)); 调用该函数

int lakenamer(lakenum) {
  char lname[20] = "0";

  if (lakenum == 1) {
    strncpy(lname, "Ontario", 20);
  } else if (lakenum == 2) {
    strncpy(lname, "Erie", 20);
  } else if (lakenum == 3) {
    strncpy(lname, "Huron", 20);
  } else if (lakenum == 4) {
    strncpy(lname, "Muskoka", 20);
  } else if (lakenum == 5) {
    strncpy(lname, "Simcoe", 20);
  }

  printf("%s",lname);
  return (lname);
}

Answer 1

如果要在函数外使用字符串，则需要在函数内为该字符串动态分配内存。

char* lakenamer( int lakenum )
{
    char* lname = ( char* )malloc( 20 );
    if ( lakenum == 1 )
    {
        strncpy( lname, "Ontario", 20 );
    }
    else if ( lakenum == 2 )
    {
        strncpy( lname, "Erie", 20 );
    }
    else if ( lakenum == 3 )
    {
        strncpy( lname, "Huron", 20 );
    }
    else if ( lakenum == 4 )
    {
        strncpy( lname, "Muskoka", 20 );
    }
    else if ( lakenum == 5 )
    {
        strncpy( lname, "Simcoe", 20 );
    }
    printf( "%s", lname );
    return ( lname );
}

int main()
{
    int lakenum = 1;
    char* s = lakenamer( lakenum );
    printf( "%s", s );

    /*
    .
    .Do other stuff with s
    .
    */

    free( s ); // Very important !!
}