How to Replace All Occurrences of a Substring in a String in C - Step by Step Examples

How to Replace All Occurrences of a Substring in a String in C ?

Answer

To replace all occurrences of a substring in a string in C, you can iterate over the string and perform the replacement manually.

✐ Examples

1 Replacing Substring "Hello" with "Hi"

In this example,

We create a string named str.
We define a function named replaceSubstring to replace all occurrences of a substring with another substring.
We call the replaceSubstring function with the substring to be replaced, the replacement string, and the input string as arguments.
Finally, we print the modified string.

C Program

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

void replaceSubstring(char *str, const char *substr, const char *replacement) {
    char *pos = strstr(str, substr);
    while (pos != NULL) {
        memmove(pos, replacement, strlen(replacement));
        memmove(pos + strlen(replacement), pos + strlen(substr), strlen(pos + strlen(substr)) + 1);
        pos = strstr(pos + strlen(replacement), substr);
    }
}

int main() {
    char str[] = "Hello World Hello";
    replaceSubstring(str, "Hello", "Hi");
    printf("%s\n", str);
    return 0;
}

Output

Hi World Hi

2 Replacing Character 'o' with 'X'

In this example,

We create a string named str.
We define a function named replaceCharacter to replace all occurrences of a character with another character.
We call the replaceCharacter function with the character to be replaced, the replacement character, and the input string as arguments.
Finally, we print the modified string.

C Program

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

void replaceCharacter(char *str, char oldChar, char newChar) {
    for (int i = 0; i < strlen(str); ++i) {
        if (str[i] == oldChar) {
            str[i] = newChar;
        }
    }
}

int main() {
    char str[] = "Hello World Hello";
    replaceCharacter(str, 'o', 'X');
    printf("%s\n", str);
    return 0;
}

Output

HellX WXrld HellX

Summary

In this tutorial, we learned How to Replace All Occurrences of a Substring in a String in C language with well detailed examples.

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How to Replace All Occurrences of a Substring in a String in C - Step by Step Examples

How to Replace All Occurrences of a Substring in a String in C ?

Answer

✐ Examples

1 Replacing Substring "Hello" with "Hi"

C Program

Output

2 Replacing Character 'o' with 'X'

C Program

Output

Summary

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