Strstr Problem Solving Report

Topic Intent: Identify the target string from source string

Idea: 1. For a comparison of 2 consecutive strings, a loop is needed to find the starting position. This is titled a target and a source, you only need a loop to find the starting position within the source. For the longest common substring with 2 strings, a 2-heavy for loop is needed to find two starting positions.
2. Note the control of the For Loop end position

Initialization section:

My Code:

  if NULL Null | | > Source.length ()) {              return-1;           }                           if (target.length () = = 0)             {return 0;             }          int m = source.length ();          int n = target.length ();

1 if(Source = =NULL|| target = =NULL||2 3Target.length () >source.length ()) {4 5             return-1;6 7         }8 9         if(target.length () = = 0) {Ten  One             return0; A  -         } -  the         intm =source.length (); -  -         intn = target.length ();

The answer to the nine chapters:

if NULL NULL return -1; }

Reflection
1. The judgment of the length of target and source can return the correct result in the body of the loop, and does not need to be treated as a special case.
2. For the exception of NULL and length 0 initialization, first determine whether the null part, otherwise null when the length will be an error.
3. For a target length of 0, it can be processed by a cyclic problem.

Part of the Loop body:

My Code:

 for (int i = 0; I <= m-n; i++) {            for (int j = 0; J < N; j + +) {                
   
     8>if (Source.charat (i + j)! =
     Target.charat (j))                    {break
    
    ;                }                 
    if (j = = N-1
    )                    {
    return 
     i;                }}        }         
    return -1;  
   

The answer to the nine chapters:

A variable is defined in the outer loop, and when the inner loop ends, the value of the variable is judged. This allows you to handle special cases with a length of 0.

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Strstr Problem Solving Report