stuck in array and string compare with strcmp c

Question

stuck in array and string compare with strcmp c why ist it working?? compiler got stuck at if(strcmp(c,ch[i]) == 0){

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

int main(){
    char ch[]="asdfghjkl";
    char c;
    int n=sizeof(ch)/sizeof(char);
    scanf("%c",&c);
    for(int i=0;i<n;i++){
        if(strcmp(c,ch[i]) == 0){
            printf("%c is in %d\n",c,i+1);
            break;
        }else if(i==n-1){
            printf("%c not fond\n",c);
        }
    }
    return 0;
}

`strcmp` takes two *strings* as arguments. You are passing a `char` and a string. Doesn't your compiler complain about it? Read [How to debug small programs](https://ericlippert.com/2014/03/05/how-to-debug-small-programs/). — P.P, Aug 25 '17 at 12:49
The [`strcmp`](http://en.cppreference.com/w/c/string/byte/strcmp) function is for comparing *strings*. You want to compare *characters*. — Some programmer dude, Aug 25 '17 at 12:49
type of `c` is `char` (one character, not string). `strcmp` requires `char *`. — BLUEPIXY, Aug 25 '17 at 12:50
please please [mcve] with description of what is the *expected* result. What's wrong with `strchr`? — Antti Haapala -- Слава Україні, Aug 25 '17 at 13:09

score 1 · Answer 1 · answered Aug 25 '17 at 12:54

1

I believe your compiler should complain that you're using strcmp incorrectly: You are passing two chars to two const char*s which is definitely a UB. It'd be good if your compiler stops you from doing so by throwing an error.

The prototype for strcmp is (in string.h)

int strcmp(const char * s1, const char * s2);

Since you have two chars and char is a basic type, you can compare them directly:

if ( c == ch[i] )

answered Aug 25 '17 at 12:54

iBug

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It is not "UB", it is a constraint violation of the allowed forms of simple assignment. When passing parameters to a function, "...the arguments are implicitly converted, as if by assignment, to the types of the corresponding parameters" (6.5.2.2/7). Going from `char` to `char*` is not a valid form. Meaning that the compiler must give a diagnostic or it is not conforming. – Lundin Aug 25 '17 at 13:20

score 0 · Answer 2 · answered Aug 25 '17 at 12:53

0

Declaration of strcmp: int strcmp(const char *s1, const char *s2);

strcmp expects strings, but you are trying to pass char.

Use

if (c == ch[i])

answered Aug 25 '17 at 12:53

Ritesh

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Whats wrong in this? Can someone explain – Ritesh Aug 25 '17 at 13:03

stuck in array and string compare with strcmp c

2 Answers2