C - strcmp() not functioning correctly

Question

I am trying to write a C program to calculate the frequency of certain letters within a phrase. The program reads the phrase character by character (via an mmap that stores characters in an array) and compares the current letter to the desired letter. If there is a match, a counter increments. However, when running my code, I get strange results. The frequency is not incrementing because the letters do not match in the call to strcmp, even though they do match in the debug. What is happening within my program to cause this behaviour?

    char* data;         /* input contents from mmap */
    char* currChar;     /* character being compared to */
    char  inChar;       /* character being read */

    ...

    do {
        /* get character */
        inChar = 0;
        inChar = data[i];

        /* debug */
        printf("data[i] = %c, inChar = %c, &inChar = %c, currChar = %s\n", 
                data[i],      inChar,      &inChar,      currChar);

        /* if match */
        if (strcmp(&inChar, currChar) == 0) {
            /* increment frequency */
            freq++;
        }

        /* increment position */
        i++;
    } while (inChar != 0);

Below is sample output when trying to count the frequency of 'a' in the word "and".

data[j] = a, inChar = a, &inChar = S, currChar = a
data[j] = n, inChar = n, &inChar = S, currChar = a
data[j] = d, inChar = d, &inChar = S, currChar = a
0 instances of a

Answer 1

strcmp compares strings. &inChar is not a string.

As you've described your task, you can do the comparison with

if (inChar == *currChar)