C++流程控制中用于跳转的return和goto语句学习教程

return [expression];

// return_statement2.cpp
#include <stdio.h>

int max ( int a, int b )
{
  return ( a > b ? a : b );
}

int main()
{
  int nOne = 5;
  int nTwo = 7;

  printf_s("\n%d is bigger\n", max( nOne, nTwo ));
}

goto identifier;

// goto_statement.cpp
#include <stdio.h>
int main()
{
  int i, j;

  for ( i = 0; i < 10; i++ )
  {
    printf_s( "Outer loop executing. i = %d\n", i );
    for ( j = 0; j < 2; j++ )
    {
      printf_s( " Inner loop executing. j = %d\n", j );
      if ( i == 3 )
        goto stop;
    }
  }

  // This message does not print: 
  printf_s( "Loop exited. i = %d\n", i );

  stop: 
  printf_s( "Jumped to stop. i = %d\n", i );
}

正在执行外部循环。i = 0
 正在执行内部循环。j = 0
 正在执行内部循环。j = 1
正在执行外部循环。i = 1
 正在执行内部循环。j = 0
 正在执行内部循环。j = 1
正在执行外部循环。i = 2
 正在执行内部循环。j = 0
 正在执行内部循环。j = 1
正在执行外部循环。i = 3
 正在执行内部循环。j = 0
跳转以停止。i = 3

// transfers_of_control.cpp
// compile with: /W1
// Read input until a nonnumeric character is entered.
int main()
{
  char MyArray[5] = {'2','2','a','c'};
  int i = 0;
  while( 1 )
  {
   int total = 0;

   char ch = MyArray[i++];

   if ( ch >= '0' && ch <= '9' )
   {
     goto Label1;

     int i = ch - '0';
   Label1:
     total += i;  // C4700: transfers past initialization of i.
   } // i would be destroyed here if goto error were not present
  else
   // Break statement transfers control out of loop,
   // destroying total and ch.
   break;
  }
}