String handling using library functions - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to copy the string from source to destination using a standard library function.

C

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

int main() {
    char source[] = "Hello";
    char destination[10];
    [1](destination, source);
    printf("%s", destination);
    return 0;
}

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Astrcpy

Bstrlen

Cstrcmp

Dstrcat

Attempts:

3 left

💡 Hint

Common Mistakes

Using strcmp instead of strcpy, which compares strings but does not copy.

Using strlen which returns length, not copying.

Using strcat which concatenates strings instead of copying.

The strcpy function copies the string from the source to the destination.

2fill in blank

medium

Complete the code to find the length of the string using a standard library function.

C

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

int main() {
    char str[] = "Hello, world!";
    int length = [1](str);
    printf("Length: %d", length);
    return 0;
}

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Astrlen

Bstrcpy

Cstrcmp

Dstrcat

Attempts:

3 left

💡 Hint

Common Mistakes

Using strcpy which copies strings, not length.

Using strcmp which compares strings, not length.

Using strcat which concatenates strings, not length.

The strlen function returns the length of the string excluding the null character.

3fill in blank

hard

Fix the error in the code to compare two strings correctly using a standard library function.

C

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

int main() {
    char str1[] = "apple";
    char str2[] = "apple";
    if ([1](str1, str2) == 0) {
        printf("Strings are equal\n");
    } else {
        printf("Strings are different\n");
    }
    return 0;
}

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Astrcpy

Bstrcmp

Cstrlen

Dstrcat

Attempts:

3 left

💡 Hint

Common Mistakes

Using strcpy which copies strings, not compares.

Using strlen which returns length, not compares.

Using strcat which concatenates strings, not compares.

The strcmp function compares two strings and returns 0 if they are equal.

4fill in blank

hard

Fill both blanks to concatenate two strings safely using a standard library function.

C

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

int main() {
    char str1[20] = "Hello, ";
    char str2[] = "World!";
    [1](str1, str2, [2]);
    printf("%s", str1);
    return 0;
}

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Astrncat

Bstrcpy

Csizeof(str1) - strlen(str1) - 1

Dstrlen(str2)

Attempts:

3 left

💡 Hint

Common Mistakes

Using strcpy which overwrites instead of appending.

Using strlen(str2) which may cause overflow if str1 is small.

Not calculating buffer size correctly.

The strncat function concatenates strings safely by specifying the maximum number of characters to append. The size calculation ensures no buffer overflow.

5fill in blank

hard

Fill all three blanks to create a substring by copying part of a string using standard library functions.

C

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

int main() {
    char source[] = "Programming";
    char substring[10];
    strncpy(substring, source + [1], [2]);
    substring[[3]] = '\0';
    printf("%s", substring);
    return 0;
}

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A3

B6

D7

Attempts:

3 left

💡 Hint

Common Mistakes

Not adding the null terminator, causing garbage output.

Copying wrong number of characters.

Starting from wrong index.

The code copies 6 characters starting from index 3 of the source string. Then it adds a null character at index 6 to end the substring properly.