偶然发现了这个在线编译器，试用了一下，感觉挺好的，不需要注册，网址为：http://codepad.org/

运行下面程序：

#include

using namespace std;

void swap(char *p1, char *p2)

{

char c = *p1;

*p1 = *p2;

*p2 = c;

}

void permute(char *pStr, char *pStart)

{

char *p = NULL;

static int i = 0;

if('\0' == *pStart)

{

cout << ++i << ":" << pStr << endl;

}

else

{

for(p = pStart; *p != '\0'; p++)

{

swap(pStart, p);

permute(pStr, pStart + 1);

swap(pStart, p);

}

}

}

void printPermute(char *pStr)

{

if(NULL == pStr)

return;

permute(pStr, pStr);

}

int main()

{

char str[] = "abcde";

printPermute(str);

return 0;

}       结果为：

1:abcde

2:abced

3:abdce

4:abdec

5:abedc

6:abecd

7:acbde

8:acbed

9:acdbe

10:acdeb

11:acedb

12:acebd

13:adcbe

14:adceb

15:adbce

16:adbec

17:adebc

18:adecb

19:aecdb

20:aecbd

21:aedcb

22:aedbc

23:aebdc

24:aebcd

25:bacde

26:baced

27:badce

28:badec

29:baedc

30:baecd

31:bcade

32:bcaed

33:bcdae

34:bcdea

35:bceda

36:bcead

37:bdcae

38:bdcea

39:bdace

40:bdaec

41:bdeac

42:bdeca

43:becda

44:becad

45:bedca

46:bedac

47:beadc

48:beacd

49:cbade

50:cbaed

51:cbdae

52:cbdea

53:cbeda

54:cbead

55:cabde

56:cabed

57:cadbe

58:cadeb

59:caedb

60:caebd

61:cdabe

62:cdaeb

63:cdbae

64:cdbea

65:cdeba

66:cdeab

67:ceadb

68:ceabd

69:cedab

70:cedba

71:cebda

72:cebad

73:dbcae

74:dbcea

75:dbace

76:dbaec

77:dbeac

78:dbeca

79:dcbae

80:dcbea

81:dcabe

82:dcaeb

83:dceab

84:dceba

85:dacbe

86:daceb

87:dabce

88:dabec

89:daebc

90:daecb

91:decab

92:decba

93:deacb

94:deabc

95:debac

96:debca

97:ebcda

98:ebcad

99:ebdca

100:ebdac

101:ebadc

102:ebacd

103:ecbda

104:ecbad

105:ecdba

106:ecdab

107:ecadb

108:ecabd

109:edcba

110:edcab

111:edbca

112:edbac

113:edabc

114:edacb

115:eacdb

116:eacbd

117:eadcb

118:eadbc

119:eabdc

120:eabcd

该在线编译器有点类似于OJ系统。