Attempt at making a dumb little calculator to help me learn c type conversions.

calc.c

#include <stdio.h>

int add(int, int);
int analyze(char*);
int operate(char, int, int);


int main() {
    char input[10];
    printf("Welcome to mat's calculator 0.0.0.1\n");
    scanf("%s", input);

    printf("%d\n", analyze(input));
}

int add(int x, int y) {
    return x + y;
}

int analyze(char s[]){
    int i, operated;
    char operator;
    int num1, num2;
    for(i = 0; i < 10; ++i){
        printf("%c\n", s[i]);
        if(s[i] == '+'){
            operator = '+';
            operated = 1;
            printf("Operated, Operator == %c\n", operator);
        } else if (s[i] == ' ') {
            ;
        } else {
            if (operated == 1) {
                num2 = (num2 * 10) + (s[i] - '0');
            } else {
                num1 = (num1 * 10) + (s[i] - '0');
            }

        }
    }
    return operate(operator, num1, num2);
}

int operate(char op, int v, int z) {
    switch(op){
        case '+':
            return add(v, z);
        default:
            return -1;
    }
}