help with C, argv


 
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# 1  
Old 02-09-2011
Error help with C, argv

when i run my program, i have a parameter, that i want to set the value to another string

i am using
Code:
int main(int argc, char **argv) {

    char my_str=argv[2];
    printf("%s",my_str);

   return 0;
}

and i get
Segmentation fault

ran using
Code:
./my_prog /usr/share/dict/words hello1

but this isnt working, does anyone know why?

Last edited by Scott; 02-09-2011 at 11:17 AM.. Reason: Code tags, please...
# 2  
Old 02-09-2011
your passing the wrong type to printf. you need to pass a pointer to a string and your currently passing a char or really a int since char is typedef; enable warnings when compiling eg: gcc -Wall. also add #include <stdio.h> at the top of your source file

Code:
char *my_str=argv[2];

also - please use code tags.
# 3  
Old 02-09-2011
Or, to further an explanation, what a string really is, is a pointer to memory, telling where the string is stored. You can't store it in a single character. When printf() expects a pointer and you hand it a character, it goes to whatever garbled value got stored in your char and tries to read it, and since it's almost certainly invalid, crashes.
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