查找字符串的所有子字符串

Question

I have a string where I need to do substring operation. I'm trying to achieve something like this for example if the input string is com then the output must be something like this -

c co com o om m .. I have tried this

for(int i=0 ; i<len ;i++)
{
    printf("%s",&string[strlen(string)-i]));
}

Answer 1

A substring is defined by its left and right ends so there are O(n*n) substrings in a string of length n .

int n = strlen(string);
for(int i = 0; i < n; i++)
{   for(int j = i; j < n; j++)
    {   /* print substring from i to j */
        for(int k = i; k <= j; k++)
        {   printf("%c", string[k]);
        }
        printf("\n");
    }
}

Answer 2

You're missing a comma in your code:

for(int i=0 ; i<len ;i++)
{
    printf("%s", &string[strlen(string)-i])
}

But that will print "", "m", "om" - not what you want.

Something more like:

// start at each point in the string
for ( const char *start = string; *start; ++start )
{
  // for each starting point, go from the whole remainder down
  // to just one character
  for ( const char *end = string + strlen(string); end > start; --end )
  {
    for ( const char *s = start; s < end; ++s )
      putchar(*s);

    putchar('\n');   
  }
}

Example: https://ideone.com/XXoYv6

Answer 3

• Substring means any contiguous group of characters.
• For the n string it will generate (n*(n-1) /2) substrings.
• For example of String source = "STACK" Length of the character is 5, so it total substring would be (5(5-1) /2) = 10

We have to iterate through the first element of string and print all the substring and than onwards one by one we increment the index of i and printing the substring from range (j to k)

public void generateSubString(String source){
        char[] arr = source.toCharArray();
        for(int i = 0; i<arr.length; i++){
            for(int j = i ; j < arr.length; j++){
                for(int k = i; k<=j; k++){
                    System.out.print(arr[k]);
                }
                System.out.println();
            }

OUTPUT:

S ST STA STAC STACK T TA TAC TACK A AC ACK C CK K

Answer 4

Below is the code to find all substrings of a string in javascript without for loop, which will increase the speed of code.

const devideSubStr = (str) => {
 var totalLoop = str.length * ((str.length + 1)/2);
 // looping count
 let i = 0;
 var totalChar = 1;//character to get
 var charFrom = 0;// from which index
 var strLength = str.length;//length of digit
 while( i < totalLoop){     
      console.log(str.substr(charFrom, totalChar))
      charFrom ++;
      i ++;
      if(charFrom == strLength){
          charFrom = 0;
          strLength = strLength - 1;
          totalChar ++;
      }  
 }}