判断一个串B位于串A的位置

 1 int main (void){
 2 char* A = "abcdefgee";
 3 char* B = "bcdefg";
 4 printf("match at %d\n",bf(A,B));
 5 return 0;
 6 }
 7 
 8 int bf (const char* _A,const char* _B){
 9 int m,n,i,j;
10     m = strlen (_A);
11     n = strlen (_B);
12     i = 0;
13     j = 0;
14     while(i<m && j<n)
15     {
16         if(_A[i] == _B[j])
17         {
18             printf("OK %d %d %c %c\n",i,j,_A[i],_B[j]);
19             i++;
20             j++;
21         }
22         else
23         {
24             printf("OK %d %d %c %c\n",i,j,_A[i],_B[j]);     
25             i = i-j+1;j=0;
26         } 
27     }
28     if( j>=n ) 
29         return i-n;
30     else 
31         return 0; 
32 }