Thread: concatenating (adding) two character strings

You need to indent your code properly, e.g.,

Code:

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

//function to terminate the program incase reach of 0

int str_len(char s[])
{
    int i = 0;
    while (s[i] != NULL)
        ++i;
    return i + 1;
}

char string_cat(char *s1, char *s2)
{
    //ADDING THE TWO STRINGS
    int str_len(char s[])
    char s1 [80]= {'0'};
    char s2 [40]= {'0'};
    int len1= (int)str_len(&s1);
    int  len2= (int) str_len(&s2);
    char *strcat (s1, s2);
    return;
}

int main()
{
    char string_cat(char *s1, char *s2)
    int str_len(char s[])
    //RECIVING THE STRINGS TO ADD
    char s1 [80];
    char s2 [40];
    int i = 0;
    printf("What is the first sentence?: ")
    fgets(*s1[0], 35 + 1, stdin);
    printf("What is the second sentence?:")
    fgets(*s2[0], 75 + 1, stdin);
    if (int i = 0; len1 + len2 < 80; ++i)
    {
        string_cat(*s1, *s2);
        else
            printf("Sorry, too long of a sentence");
    }
    printf("The two sentences added together produce the following: %c", s1[])
    ++i
    return null;
}

Having indented your code a number of mistakes become evident.

For str_len:

• The parameter should be: const char s[] since str_len does not modify the string.
• NULL is a null pointer constant. You should use '\0' for a null character.
• Returning i + 1 looks wrong unless your intention is to compute string length including the null character, unlike the standard strlen.

For string_cat:

• You appear to have function declarations that are out of place.
• You need to be clear about the types, e.g., s1 is a char*, so &s1 is a char**, therefore &s1 is not a valid argument to str_len.
• Why is string_cat declared as returning a char, and why do you return nothing?
• You don't seem to have actually attempted to implement the concatenation itself.

For main:

• Once again, unnecessary function declarations.
• You keep forgetting to terminate with semi-colons.
• Once again, be careful as to type: s1 is a char*, so s1[0] is a char, hence *s1[0] does not make sense.
• Notice that your if statement is mismatched with its else branch.
• Your printf statement is incorrect: s1[] is simply invalid syntax, and since you want to print a string, you should use %s not %c.
• null is not a valid identifier. You should just return 0;