Learn C from Scratch. More C string questions There is a lot more we can do with strings in C. Take a look at some of the common interview questions about strings to get a sense of what to learn: Edit all the contents of a string Replace every character of a string with a different character Map every character of one string to another so all occurrences are mapped to the same character Modify the string so that every character is replaced with the next character in the keyboard Make an array on strings using pointers Convert all the letters in a string to Uppercase letters Convert a string to an integer Splitting a string using strtok in C What to learn next Congrats!
Happy learning! Learn in-demand tech skills in half the time. Early Access Courses. Assessments New. Free Trial New. For Business. For Educators. Become an Affiliate. Terms of Service. Business Terms of Service. Careers Hiring. For Bootcamps. Blog for Business. Quality Commitment. Contact Us. It is undefined behaviour to attempt to modify string literals, which is what something like: strcat "Hello, ", name ; will attempt to do. Try something this. It achieves what you appear to be trying to do: char message[]; strcpy message, "TEXT " ; strcat message, var ; This creates a buffer area that is allowed to be modified and then copies both the string literal and other text to it.
Then you will get a buffer overflow, which you can add code to check for beforehand say, with strlen. But the purpose of a code snippet is to show how something works without polluting it with too much extra code.
That makes your answer dangerous. You also didn't explain why this code is better than the OP's original code, except for the myth that it "achieves the same result as your original" then what would be the point? Have hopefully addressed your concerns, PreferenceBean, though in a less timely manner than ideal :- Let me know if you still have a problem with the answer, and I'll improve it further.
And now an important point: Ensure that the buffer has enough space to hold the text AND the null character. Ralf Ralf 3 3 silver badges 4 4 bronze badges. For backward compatibility reasons, string literals are not const , but attempting to modify them results in undefined behavior. Nils Nils You want "string.
You also calculate strlen s1 twice, which isn't needed. MooingDuck: "string. I haven't used C-style strings for a while. Feel free to post a fixed version. MooingDuck: That's incorrect. Note that this depends on Cspecific features: mixing declarations and statements, and variable-length arrays VLAs.
Note also that VLAs provide no mechanism to detect or handle allocation failures; if there isn't enough room to allocate a VLA, your program's behavior is undefined. Pieter Pieter Donald Duck Donald Duck 7, 19 19 gold badges 65 65 silver badges 86 86 bronze badges. So can you really write your own function?
You never free the memory, nasty, nasty! Can you see now why you don't have to write your own function? Liviu I do free the memory at the line free buffer ;. Show 10 more comments. Todd Todd 2, 14 14 silver badges 11 11 bronze badges. Note 3, if you are already using printf anywhere in your program there is no reason not to use snprintf , since the compiled code would be larger but inlined and significantly faster.
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Now live: A fully responsive profile. Linked 4. Warning: When using character pointers, care must be taken so that the source and destination aren't overlapped. Following is an example of ill-formed code which uses strcat of overlapped buffer - which causes undefined behaviour:. The strncat function is used to append at most n characters from source string to destination string. Here is an example:. The example above will append first 4 characters from src at the end of dest i.
Warning: The destination character array must be large enough to hold all characters of destination, n characters of source and a NULL character. Following is an example of an ill-formed code which violates this rule:. Character pointers can be used to the parameters of strncat :. In the example above, ps points to the 5th character of src that's the space. Warning: When using character pointers be careful to the fact that the source and the destination cannot be overlapped.
Count the Number of Vowels, Consonants and so on. Find the Frequency of Characters in a String. Related Topics Find the Length of a String. String Examples in C Programming. C Program to Concatenate Two Strings In this example, you will learn to concatenate two strings manually without using the strcat function. Share on:. Did you find this article helpful? Sorry about that. How can we improve it?
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