C语言整型转为字符型

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

int cti(char c)
{
    int num = 100;
    if(c=='0')
        num = 0;
    else if(c=='1')
        num = 1;
    else if(c=='2')
        num = 2;
    else if(c=='3')
        num = 3;
    else if(c=='4')
        num = 4;
    else if(c=='5')
        num = 5;
    else if(c=='6')
        num = 6;
    else if(c=='7')
        num = 7;
    else if(c=='8')
        num = 8;
    else if(c=='9')
        num = 9;

    return num;
}

int main()
{
    char s[14];
    scanf("%s",s);
    int count = cti(s[0])*1+
    cti(s[2])*2+cti(s[3])*3+cti(s[4])*4+
    cti(s[6])*5+cti(s[7])*6+cti(s[8])*7+cti(s[9])*8+cti(s[10])*9;
    int flag = count%11;
    char c;
    if(flag ==10)
        c = 'X';
    else
        c = flag+'0';
    if(s[12]==c)
        printf("Right\n");
    else
    {
        s[12]=c;
        printf("%s\n",s);
    }
    return 0;
}