How to return a string in a C function?

Question

I have to make a function that has a float as parameter, and the function will return that number in words (As a string)

i.e: function(12.0) will return twelve as a string

But I have some problems returning the string, it returns some weird data, I have this code:

            char* function (float number)
            {
                char str[] = "test";
                strcat(str, " char");
                return str;
            }

            int main()
            {
                char *test = function(5.0); 
                printf("Hi %s", test);
            }

That always returns a different thing:

            Hi u.ª╣D
            Hi uêõWÛ

I don't know how to fix it, because I really need to use strcat to do things like 'one thousand ten' saving time and lines of code, and it's not possible if I define char str as a pointer...

I'm using Dev-C++ 5.11

Thank you!

I searched a few days but noone of the answers worked with what I need, because they define the string as a pointer or use more than 1 parameter in the function (it only has to receive 1 float parameter, no more parameters are accepted)

score 1 · Accepted Answer · answered Oct 10 '18 at 14:50

1

str is local to function and will be destroyed once control exits function.

Hence you can try as below.

            char* function (float number)
            {
                char *str = malloc(30);
                strcpy(str, " test");
                strcat(str, " char");
                return str;
            }

            int main()
            {
                char *test = function(5.0); 
                printf("Hi %s", test);
            }

answered Oct 10 '18 at 14:50

kiran Biradar

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Why `5.0` as an argument? – Gaurav Oct 10 '18 at 15:01
@Observer OP wants to convert float to string, He was struck with returning string from the function. I just focused on how to return string from function. – kiran Biradar Oct 10 '18 at 15:03
I tried your code, but it has an error: [Error] invalid conversion from 'void*' to 'char*' [-fpermissive] – sort72 Oct 10 '18 at 15:06
2

@Muschel Are you using c++ compiler. if yes cast the `malloc` return to `char *` like this (`char *str = (char*)malloc(30)`). – kiran Biradar Oct 10 '18 at 15:08

How to return a string in a C function?

1 Answers1