Print the string after the specified character has occurred given no. of times in C Program

In C programming, we often need to extract a substring after a specific character has occurred a certain number of times. This task involves scanning through a string and printing all characters after the nth occurrence of a specified character.

Syntax

for (i = 0; i < string_length; i++) {
    if (count > 0) {
        if (string[i] == target_char) {
            count--;
        }
        continue;
    }
    printf("%c", string[i]);
}

Algorithm

START
Step 1 ? Input character (e.g. 'a') and count (e.g. 2)
Step 2 ? Declare string and calculate its length
Step 3 ? Loop through each character in the string
   IF count > 0
      IF current character matches target character
         Decrement count
      End IF
      Continue to next character
   End IF
   ELSE
      Print current character
   End ELSE
Step 4 ? End Loop
STOP

Example

The following program prints the string after the character 'a' has occurred 2 times −

#include <stdio.h>
#include <string.h>

int main() {
    char string[] = "I am Harsh Vaid";
    char ch = 'a';
    int count = 2;
    int n = strlen(string);
    
    printf("Original string: %s<br>", string);
    printf("Character to find: '%c'<br>", ch);
    printf("Occurrence count: %d<br>", count);
    printf("Result: ");
    
    for(int i = 0; i < n; i++) {
        if(count > 0) {
            if(string[i] == ch) {
                count--;
            }
            continue;
        }
        printf("%c", string[i]);
    }
    printf("<br>");
    
    return 0;
}

Original string: I am Harsh Vaid
Character to find: 'a'
Occurrence count: 2
Result: rsh Vaid

How It Works

• The program iterates through each character of the string
• When count > 0, it looks for the target character and decrements the counter
• Once the specified number of occurrences are found (count = 0), it starts printing the remaining characters
• The continue statement skips printing until the target occurrences are reached

Key Points

• Use strlen() instead of sizeof() for proper string length calculation
• The algorithm has O(n) time complexity where n is the string length
• If the character doesn't occur the specified number of times, nothing is printed

Conclusion

This approach efficiently extracts substring after nth occurrence of a character using a simple counter mechanism. The method is straightforward and handles edge cases where the character may not appear enough times.