How to Insert Character at Specific Index in String in C - Step by Step Examples

How to Insert Character at Specific Index in String in C ?

Answer

To insert a character at a specific index in a string in C, you can use a loop to shift the characters following the specified index one position to the right before inserting the new character.

✐ Examples

1 Insert Character at Specific Index in String

In this example,

We create a string array named str with an initial value and a sufficient buffer size to accommodate the new character.
We specify the index index at which the character needs to be inserted and the character ch to be inserted.
We use a loop to shift all characters after the specified index one position to the right.
We insert the new character at the specified index.
Finally, we print the modified string to the standard output.

C Program

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

void insertCharAtIndex(char* str, char ch, int index) {
    int len = strlen(str);
    for (int i = len; i >= index; i--) {
        str[i + 1] = str[i];
    }
    str[index] = ch;
}

int main() {
    char str[50] = "Hello World";
    char ch = 'X';
    int index = 5;
    insertCharAtIndex(str, ch, index);
    printf("Modified string: %s\n", str);
    return 0;
}

Output

Modified string: HelloX World

2 Insert Character at Another Specific Index in String

In this example,

We create a string array named str with an initial value and a sufficient buffer size to accommodate the new character.
We specify the index index at which the character needs to be inserted and the character ch to be inserted.
We use a loop to shift all characters after the specified index one position to the right.
We insert the new character at the specified index.
Finally, we print the modified string to the standard output.

C Program

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

void insertCharAtIndex(char* str, char ch, int index) {
    int len = strlen(str);
    for (int i = len; i >= index; i--) {
        str[i + 1] = str[i];
    }
    str[index] = ch;
}

int main() {
    char str[50] = "ProgramGuru";
    char ch = 'M';
    int index = 4;
    insertCharAtIndex(str, ch, index);
    printf("Modified string: %s\n", str);
    return 0;
}

Output

Modified string: ProgMramGuru

Summary

In this tutorial, we learned How to Insert Character at Specific Index in String in C language with well detailed examples.

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