判断字符串是否为数字

此代码还有缺陷，仅供参考。51Testing软件测试网4_NB%}9ye8Z#h!D'H5R

#include<stdio.h>

/****************判断函数****************************/

fc \B5c$XMZ_?!b9f0int checkisnum(char *source)
l/LE4t \ a
}9Z&z N!T0{51Testing软件测试网p&}4uC-O6i:d2@ Q%Agp
    int i=0;
Qc}4xn;w0    int temp=0;
eVZQl$W0    int flag=1; //falg=1 有效数字 
;dA)a5V J0q#A0    int len = strlen(source);51Testing软件测试网+ZAbKt+ZL^l
    for(i=0;i<len;i++)
a\'c'm;nbE{Q2y0    {
3\];B ? HG+^0         if(!(source[i]>=48&&source[i]<=57 || source[i]==46|| source[i]==45))//判断数字的组成 51Testing软件测试网$~:MNIS'A-yl
            flag=0;

          if(source[i]==46||source[i]==45)//判断多个符号.或者-存在的情况 
BO3B/]B)p^0D0         {
Xu
H"D9dC
k"u'W0            temp++;
A.`2nUy&e"z+k} p0            if(temp>1)
9R`4mG)A!X0               flag=0;51Testing软件测试网)];afQ,Q$Gw
         } 51Testing软件测试网EBmKd"CR Do
    }

P `U2T8lB0    if(source[0]==46 || source[len-1]==46 || source[len-1]==45)//'.'在开头结尾，-在结尾 51Testing软件测试网)mhS3H/fD
         flag=0;
*At5IA^ng7h0    if(len==1)//-
];fN8i\q4[:O0    {
7xq'B$`0@1ip D&X3Vh0H0              if(source[0]==45)
+C*XFcR z&a+R0              flag=0;
}V)wO x?M0    } 51Testing软件测试网]zP
V`5W f3O
    if(len>=2)
}#\C d-F!x%U0    {
8f/ND%ks5{'R(Oz
l0           if(source[0]==45&&(source[1]==46||source[1]==48))//-./-0xxxx
WeW4a rI"mA$kg,X0               flag=0;51Testing软件测试网k+i zS}2J w$d%R1}0y
           if(source[0]==48&& source[1]!=46)//0.xxx
g3F I2A kp-Z%H0               flag=0;
kj8Dzu-Sw0    }51Testing软件测试网Cy.l'[+@-T'w
   printf("输入的字符串是：%s 检测结果：%d\n",source,flag);
._|EN;K)D0   return flag;
3E*Z(|gC6@0    51Testing软件测试网Bv~9X-TU$F
}51Testing软件测试网m7D+sKD"D,L

/********************测试代码*******************************/

L7f;t%N;XzpT w/uN0void testnumber(char * str,int expect)
;}-VZ;}2~"i\-H$t%sEg0{51Testing软件测试网8X7A'_@\
H9b/Iu
     int actual=checkisnum(str);
H-m8?#b*KQZW@ N*SG.m0     if(actual==expect)
-|Y)SE}"C"Es"M-C0     printf("Success\n");51Testing软件测试网{DQmm*v
     else
^0x*f)j,X$K!`'P d0     printf("Failure\n");
+H"rZPd@iY1K|0}

int main()

{

   testnumber("2kj",0);51Testing软件测试网A9ic6T6N,mf `$NrT
   testnumber(".123",0);
@(TD YVT!C0   testnumber("..123",0);
T4@V8H-R2l1x0   testnumber("0.123",1);
$W\"pc0W0   testnumber("-123",1);51Testing软件测试网 P?/U2o
{+es
   testnumber("-.123",0);51Testing软件测试网D5Pz_4}*Qw
   testnumber("-12.3",1);51Testing软件测试网LlQa2[uCq(c.?
   testnumber("1234",1);
3fa:D(A*xzO_0   testnumber("0",1);51Testing软件测试网1RZ#D8f:d
   testnumber("-0",0);51Testing软件测试网)HjI.}7x!w2R
   testnumber("-12as3",0);51Testing软件测试网^1pc;S^DPv|&X
   testnumber("123-",0);
!F%nw Q6BU0   testnumber("-1.2-3",0);
F lz Ht o$Hn0   testnumber(".-123",0);
`g[`&D\#L
a0   testnumber("-a123",0);
m+z]IG-{I:|0   testnumber("0123",0);51Testing软件测试网F
B8g-^(\Y1a
   testnumber("10.12.45-5",0);
H v9I^*kZ*aq1mUb0   testnumber("-10.23.",0);51Testing软件测试网'l'K+F4TR)LWa3q?x
   testnumber(".",0);

  getchar();51Testing软件测试网,U6@1a&F `5mf,G
  return 0;

}51Testing软件测试网1p:I s#~$^(gG,E1g