How to find index of same char in an array in C-CodePudding

I am wondering if it is possible to compare a char with an array with chars and find the index with the same characters

In python, you could use the index method:

colors = ['red', 'green', 'blue']
y = 'green'
x = colors.index(y)
print(x)

This would print:

How could you do this in C?

CodePudding user response：

To find an exact match (implemented as a function,) it is also possible to 'borrow' from the lesson given by char *argv[]. If the list (in this case colours) has as its final element a NULL pointer, that fact can be used to advantage:

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

int index( char *arr[], char *trgt ) {
    int i = 0;
    while( arr[i] && strcmp( arr[i], trgt) ) i  ;
    return arr[i] ? i : -1;
}

int main() {
    char *colors[] = { "red", "green", "blue", NULL };

    printf( "%d\n", index( colors, "green" ) );

    return 0;
}

One could/should also test function parameters have been supplied and are not themselves NULL values. This is left as an exercise for the reader.

CodePudding user response：

You can use strcmp() to compare two strings character by character. If the strings are equal, the function returns 0.

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

int main() {
    char *colors[] = {"red", "green", "blue"};
    char *y = "green";
    int x = -1;
    for (int i = 0; i < 3; i  ) {
        if (strcmp(colors[i], y) == 0) {
            x = i;
            break;
        }
    }
    printf("%d\n", x);
    return 0;
}