CODEWITHSUNDEEP
carraysstringcharformat
Alexandru Dinu
Alexandru Dinu

Reputation: 1267

Replace char with a string or another char

Suppose I have an array of chars, just like this: 

abc def ghi jkl ...

where words are separated just by spaces.

My goal is to replace all the existing spaces with some other strings (chars) I wish. For example: 

abcMNPdefQRTghiXYZjkl

I thought about creating a function named replace that may do the following: 

void replace(char *str, int pos, char *rep)
{
    //get length of rep
    //pos = position of the blank which i want to replace with rep
    //code to do the replacement
}

My initial idea was to shift right the elements of str bystrlen(rep)and then insert rep.

Is the idea any good or is there any other better method?

Upvotes: 0

Views: 253

Answers (2)

jim mcnamara
jim mcnamara

Reputation: 16389

Another way - just as unsafe as Michal.z's version assuming pos is the zero based position:

void replace(char *str, int pos, char *rep)
{
    char *tmp=strdup(&str[pos+1]);
    strcat(&str[pos], rep);
    strcat(str, tmp);
    free(tmp);    
}

str has to have enough space to accommodate strlen(rep) more characters, or the code will fail. A safer version would have to total space available so you could check and not insert something too large. Or malloc a completely new string, and return the new string.

Upvotes: 1

michal.z
michal.z

Reputation: 2075

//replace specified chunks in a string (size-independent, just remember about memory)
void replcnks(char *str, char *cnk1, char *cnk2)
{
    char *pos;
    int clen1 = strlen(cnk1), clen2 = strlen(cnk2);
    while(pos = strstr(str, cnk1))
    {
        memmove(pos + clen2, pos + clen1, strlen(pos) - clen1 + 1);
        memcpy(pos, cnk2, clen2);
    }
}

Upvotes: 1

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