C language about using SSCANF to implement string addition and subtraction

#include <stdio.h>
#include <string.h>
void Main () {

int A;

int b;

Char str1[10] = "99999";
Char str2[10] = "1111111";
Char str[30];
int k = 0, i = 0, j = 0;
for (k = 0; k < 30&&i<strlen (str1);) {
str[k++] = str1[i++];
}
Str[k] = ' + ';
Str[++k] = 0;
strcat (str, str2);
SSCANF (str, "%d+%d", &a, &b);
printf ("%d\n", A + B);
}

The above program realizes the STR1 and str2 string addition and subtraction, why add ' + ' in the middle of STR, is to be able to construct a regular pattern in accordance with the "%d+%d" format in sscanf, the above is to use the regular type of sscanf to easily implement the string addition and subtraction

Boring yards a yard, a lot of fun

C language about using SSCANF to implement string addition and subtraction