How to find the Indices of All Occurrences of Substring in C - Step by Step Examples

How to find the Indices of All Occurrences of Substring in C ?

Answer

To find the indices of all occurrences of a substring in C, you can use loops to iterate through the string and compare substrings to find matches.


✐ Examples

1 Find Indices of All Occurrences in String

In this example,

  1. We create a string array str with a string value.
  2. We create a string variable substr to store the substring we want to find.
  3. We use a loop to iterate through str and compare substrings to substr to find matches, storing their indices.
  4. We print the indices of all occurrences.

C Program

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

int main() {
    char str[] = "Hello Hello Hello";
    char substr[] = "Hello";
    int indices[10];
    int count = 0;
    for (int i = 0; i < strlen(str); i++) {
        if (strstr(&str[i], substr) == &str[i]) {
            indices[count++] = i;
        }
    }
    printf("Indices of all occurrences: ");
    for (int j = 0; j < count; j++) {
        printf("%d ", indices[j]);
    }
    return 0;
}

Output

Indices of all occurrences: 0 6 12

2 Find Indices of All Occurrences in Another String

In this example,

  1. We create two string arrays str and substr with different values.
  2. We use a loop to iterate through str and compare substrings to substr to find matches, storing their indices.
  3. We print the indices of all occurrences.

C Program

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

int main() {
    char str[] = "apple banana cherry banana";
    char substr[] = "banana";
    int indices[10];
    int count = 0;
    for (int i = 0; i < strlen(str); i++) {
        if (strstr(&str[i], substr) == &str[i]) {
            indices[count++] = i;
        }
    }
    printf("Indices of all occurrences: ");
    for (int j = 0; j < count; j++) {
        printf("%d ", indices[j]);
    }
    return 0;
}

Output

Indices of all occurrences: 6 20

Summary

In this tutorial, we learned How to find the Indices of All Occurrences of Substring in C language with well detailed examples.


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